So, I've been trying to get the "complete the majority of the game" achievement, and it's tough. There's A LOT to do in this damn game. So I've been scrounging the interwebs for some information, and I have found numerous different sites that, personally, I am sick of navigating. So, I decided to help myself and the rest of you ME fans out by making one thread with as much information as possible. I got tired of navigating 15 different windows for information. I hope this helps.
Again, this MAY CONTAIN SPOILERS. So do not read further if you don't want certain information revealed.
ALL SIDE QUESTS (and how to initiate them)
original list found
HERE.
Keep in mind a lot of quest names change after you go further into depth.
Citadel: Asari Consort
-speak to the consort. can be done anytime
Citadel: Doctor Michel is Safe
-speak to Dr Michel in the medbay. sometime after leaving citadel
Citadel: Family Matters
-speak to people in the financial district. sometime after leaving citadel
Citadel: Homecoming
-speak to man in embassy lobby. after saving tali
Citadel: I Remember Me (requires Colonist background)
-head down elevator from spaceport. sometime after leaving citadel
Citadel: Jahleed Arrested/Jahleed and Chorban
-speak to jahleed in u-sec hq
Citadel: Negotiator's Request
-speak to man outside flux. after third story planet
Citadel: Old Friends (requires Earthborn background)
-speak to man in room on way to chora's den. sometime after leaving citadel
Citadel: Old, Unhappy, Far-Off Things (requires Spacer background)
-speak to man in ward entry corridor. sometime after leaving citadel
Citadel: Our Own Worst Enemy
-speak to man at viewpoint in upper wards. after third story planet
Citadel: Planting a Bug
-speak to woman in citadel tower. must have done reporter's request. sometime after leaving citadel
Citadel: Presidium Prophet
-speak to either the guard or hanar in plaza near the citadel tower. after saving tali
Citadel: Reporter's Request
-speak to woman in upperward near the view point. need access to wards
Citadel: Rita's Sister is Safe
-speak to woman in flux. need access to wards
Citadel: Scan the Keepers
-speak to man scanning the keeper's after speaking to council the first time
Citadel: Schell's Scanner Given Away/Schells Has His Data
-speak to man kicked out of flux's. sometime after leaving citadel
Citadel: Signal Tracking
-examine computer in back of flux gambling area. need access to wards
Citadel: The Fan
-speak to man in upper markets. need access to wards
Citadel: The Fourth Estate
-speak to reporter in c-sec hq. sometime after leaving citadel
Citadel: Xeltan Convinced
-while speaking to septimus for consort quest, tell him you'll do a task for him. need access to wards
Noveria: Espionage
-speak to turian in hotel bar after speaking to the salarian in his office
Noveria: Smuggling
-speak to hanar merchant
Feros: Data Recovery
-speak to man in the underground camp halfway through the skyway
Feros: Geth in the Tunnels
-speak to leader of camp
Feros: Power Cells
-speak to woman near entrance to camp
Feros: Varren Meat
-speak to man in the trailer in the camp
Feros: Water Restoration
-speak to a woman near entrance to camp
Virmire: Kirrahe's Team Rescued
-automatic while doing story mission
Virmire: Wrex is Convinced/Wrex is Dead
-automatic while doing story mission
UNC: Whatever
-all of these require visiting the necessary planet/system, hacking the necessary computer, or overhearing the necessary news blip while in an elevator. often multiple ways to start the quests
Asari Diplomacy
-speak to woman in embassy lounge after she contacts you. after leaving citadel
Garrus: Dr. Saleon is Dead
-speak to garrus often and either choose all paragon or all renegade options. choosing neutral options didn't seem to lead to him giving the quest
Tali's Pilgrimage
-pick up an item during depot sigma-23 mission
Wrex: Family Armor
-either visit the requisite planet or speak to wrex multiple times
UNC SIDE QUESTS
original found
HERE.
UNC: Missing Survey Team
You can "find" this quest by riding the elevators on Citadel Station; we obtained it just as we were heading up to see Udina and Anderson before obtaining the Normandy for our own. It indicates that a survey team in the Hades Gamma cluster has dropped out of contact. Head to the Antaeus system and land on Trebin to track them down.
When you land, check out the prefabricated pods at the survey team's site; one of the computer consoles there indicates that the team unearthed alien technology. If you head into the digsite, you'll find that they've all been turned into Husks. Whoops! Kill them all to end the mission.
UNC: Major Kyle
If you head to the Hawking Eta cluster, you'll pick up this quest. A man named Major Kyle has set up a messianic cult. It's up to you to investigate and see if you can get Kyle to return for treatment. Head to the system in the Hawking Eta cluster and land on the small moon Presrop there.
When you reach the compound, you'll need to talk your way inside the building. You can try and talk your way inside, if you like, or simply storm the place. If you do manage to convince Kyle to see you, you can find him in the science station, a bit away from the main building here. If you have enough Charm or Intimidate, you can convince him that either he surrenders himself, or the entire base will be held responsible for the deaths of the investigators. He'll offer to surrender, but will need you to leave him behind while he explains his surrender to his followers. If you return to your ship, you can click on the map to conclude the mission.
On the other hand, if you decide to fight your way through the compound, you can then clear out the science station and still talk Kyle into coming with you, or simply shooting him and finishing off his followers. You gain a lot of paragon points for talking down Kyle, but you don't necessarily gain renegade points for killing him, if you say that he's leaving you no other option. Killing everyone also nets you a lot more experience and cash than the peaceful method.
UNC: Missing Marines
If you speak to Admiral Kahoku in the Council Tower after becoming a Spectre (you can also follow the Banes trail from Michel's blackmailing mission to Anderson to him), he'll ask you find out what happened to a team of marines that have gone missing in the Sparta System. Obviously enough, they were kicked down a well after their diplomatic overtures were rebuffed.
Head to the Artemis Tau cluster, Sparta system, then land on planet Edolus. You'll have to fight off a Thresher Maw to find the marines, but when you do, it'll appear that a distress beacon was used to lure them into the Maw's area of influence and kill them. Return to Kahoku to turn in the quest.
UNC: Cerberus
After handing in the Missing Marines quest, this assignment will probably appear as you travel around the galaxy. It involves a Cerberus outpost on the planet Binthu, in the Yangtze system in the Voyager cluster. Go there and investigate all three of the Cerberus bases; one of them will have Kohaku's body in it. Find it and return to the Normandy to start...
UNC: Hades' Dogs
When you return to the Normandy, you'll be able to track down the main Cerberus base. It's on Nepheron in the Columbia System, Voyager Cluster. Head there and kill everything you see! You'll find a terminal in the rear of the facility; grab the data on it to end the mission. When you return to the ship, you'll be contacted by an agent of the Shadow Broker; you can choose whether or not to sell him the data, but doing so is a renegade move.
UNC: Lost Module
When you arrive in the Attican Beta Cluster, you'll receive a message asking you to travel to the Hercules system there to find a data module that's crashed on the planet. Land on Eletania when you reach the system and make your way to the module.
You'll discover that a monkey from one of the monkey tribes nearby has apparently stolen the data disc. Head to the northernmost monkey colony on your map to find a set of caves; one of the monkeys in the rear room will have the data disc. Grab it from him and fight your way through the Geth to finish the mission.
UNC: Hostage
Another quest you'll probably pick up by riding an elevator in the Citadel. This one explains that a politician has been kidnapped by biotics, who are on a freighter in the Hades Gamma cluster, Faranita System.
Head there and board the MSV Ontario. You only have three minutes to kill all of the biotics in the first large room here; any longer, and they'll kill the hostage. It shouldn't be too hard to take them all down in that timeframe, though. When you do, you'll have to enter negotiations with their leader. If you don't have the proper Charm/Intimidate skills, the hostage will probably die; otherwise, you can convince the remaining biotics to surrender.
UNC: Asari Diplomacy
In your travels, you'll eventually find a datapad from a mercenary named Dahlia Dantius, who was threatening her diplomat sister on the Citadel. There's probably a starter quest for this, but we happened to run into Dahlia on an otherwise unremarkable planet and killed her. If you return to Nassana, in the embassy bar on the Citadel, you can try to sweettalk her into letting you buy prototype Asari weapon mods.
UNC: Rogue VI
You'll obtain this mission after warping into a system; you'll receive a communication from Admiral Hackett telling you to return to Sol and help defeat a training VI that's gone rogue.
Head to the Local Cluster and find the tiny dot near Earth that indicates Luna's presence. Land on it, find the facility, then use one of the entrance consoles on the structures outside after defeating the turrets. Inside, you'll find a swarm of assault bots, as well as eight VI conduits. Destroy the conduits, then repeat the process at each of the other facilities to finish the VI off entirely. (The binary text you get at the end of the mission simply reads "HELP".)
You'll be able to select a specialization for your class at the end of this mission, for some reason. This will be different for each character class, so read your options carefully! The choice that you make will be added to your skill tree on top of the default character class skill. E.g. our engineer selected to be an Operative, so the Engineer skill had five or six ranks added to the end of it with added bonuses for the electronics and decryption skills.
A lot of the quests are found like this, with you hacking into enemy terminals.
UNC: Beseiged Base
After warping to a system (for us, it was the Gagarin system in the Armstrong Nebula), you'll receive a transmission about a beseiged research facility in the Cacus System of the Hades Gamma cluster. You'll have to find some way to eliminate the biotic terrorists while saving the researchers.
Head to Chohe, in the Cacus System of the Gamma Hades Cluster. You need to kill the biotics here without harming the scientists. The scientists will wander around the combat area, getting in your line of fire, so you have to be careful. The best way to proceed here will be to enter the combat zone and try to lure the biotics back through the hallway towards the entrance. When the bulk of them are cleared out, you can make your way through the rest of the facility, trying to avoid getting anywhere near the scientists; that'll help you avoid hurting them by accident. When all of the biotics are down, return to the Normandy and use the map to relay the info to Admiral Hackett.
UNC: Distress Call
If you head to the Hydra System of the Argos Rho Cluster and attempt to investigate the planet Metgos, you'll receive a distress call from a ship that's crash-landed there. Land on the planet, find the wreckage, defeat the Geth ambush, and move on.
UNC: Lost Freighter
We never actually got the starter quest for this assignment, but we stumbled across a freighter in the Ming system of the Gemini Sigma cluster. After boarding the ship, you can play the logs of the crew to discover that a biotic named Julia went crazy after her boyfriend was about to be taken off life support. She's killed the crew, but she won't be able to do much to you. Kill her, then make the call as to whether or not you want to take Jacob off life support.
UNC: Espionage Probe
If you enter the Voyager Cluster and head to the Amazon system, you'll receive this quest. Apparently a booby-trapped probe has landed somewhere in the Voyager Cluster. You need to find it and dismantle it before anyone else does.
You can head down this hill and hop into the Mako to finish off your foes relatively easily.
Head to the Amazon system and land on Agebinium. The probe is located in a set of caves. Unfortunately, when you get there, it's apparent that the caves are a trap! For you! Personally!
The nuke will have three hardpoints on it that need to be disabled. The minigames here are easier than they normally are, but if you have the omni-gel it's probably easier to simply spend it to disable them. When you do that, take the back exit to come out on top of a hill above your enemy's position. You can charge down the hill to the Mako there and use it to clear out your foes, then return to the Normandy.
Missing Person/UNC: Privateers
In Noveria, you can hack a computer in the Sythentic Interests office to receive this quest. A man named Garoth is worried about his brother, whose ship was attacked by privateers in the Strenuus System.
You won't have to travel far to reach Strenuus; it's just on the other side of the Horse's Head galaxy, where Noveria is also located. It can be tough to spot what you're looking for here, especially on an SDTV, but just to the left of Xawin there's a hotspot in the system. Scan it, then land on Xawin. The privateer camp there will have Willem's body in it, along with a datapad. Bring it back to Garoth in the Citadel Tower to end the mission.
UNC: Derelict Freighter
You'll find a drifting freighter in the Caspian system of the Maroon sea. Head on board, kill the Husks, then check the navigation log to discover the true fate of the crew.
UNC: Listening Post Alpha
Head to the Styx Theta Cluster and proceed to the Erebus System. A listening post on the planet Nepmos there is being overrun by alien forces. Time for you to intervene.
Land on Nepmos and make your way to the listening station. You may spot rachni on the way there. When you arrive, defeat the Rachni nearby, then speak to Lieutenant Durand; there's another large group of rachni coming your way! You can choose to fight them on foot by using the Mako to power the turrets here, or get into the Mako itself and use that in combat. Keep in mind that the rachni's acid breath will ignore the Mako's shields, though.
Take down the rachni and flush out the cave nearby to end this mission.
We decided to use the generator and power up the turrets. Durand and her men are seemingly indestructible here, so stay back behind the barriers and position your teammates between two of them to fire away while you hold the rear. If one of them goes down, use Unity and bring them back to you until you're in the clear.
You may have to defeat two waves of Rachni here; we did, at any rate. After you do, Durand will ask you to check in on an outpost that's gone offline, as well as clear out the main concentration of Rachni underground. You may have already cleared out the outpost, but in any case, you'll want to check out the mine. If you can head in there and clear the place out, including the two Brood Warriors in the small rooms, you will be successful in eliminating the Rachni from Nepmos.
UNC: Depot Sigma-23
If you land on the planet Altahe in the Archeron system in the Styx Theta cluster (preferably after completing the Listening Post Alpha quest), you can find another listening post there. Kill the rachni around it and check the terminal inside to find the source of the rachni invasion: Depot Sigma-23 in the Gorgon System in the Argos Rho cluster.
Head there and land on the "unidentified space facility" to uncover the mystery. You'll have to kill the rachni here to find the terminal. Play all of the entries, then set the charges on the ship and book it before the place blows.
UNC: Dead Scientists
A group of UNC scientists has been winding up dead lately, and Hackett thinks that there may be some kind of coverup involved. All of the scientists that have died worked on the same project, but one scientist from the experiment is still alive. He's in the Newton system of the Kepler Verge. Head there and land on Ontarom.
All Toombs wants is a little closure.
When you enter the underground facility and kill the mercs, you'll come across Dr. Wayne and one Corporal Toombs. Toombs has some interesting accusations about Wayne. You can attempt to talk down Toombs, but you may need to have some Charm points in order to do so. Otherwise, you can let him shoot the good doctor, or take down Toombs with violence. Either way, completing the conversation will end the mission.
Investigate Facility/UNC: Exogeni Facility
You'll find this quest by hacking into an ExoGeni terminal on Feros. Apparently they had a facility on Nodacrux, and suspect that it somehow caused the facility to shut down. Time to investigate. Travel to the Vostuk System in the Maroon Sea cluster to find the facility.
After defeating the Thorian Creepers inside the facility, you can make your way to the main scientist here. If you attempt to arrest her, she'll try to kill you. You can either pursue that course of action or accept her payout and let her leave.
Mass Effect side quests, mineral locations, and general info *SPOILER WARNING* 
Will need to get that on my hardcore playthrough.
