NOTE: As their name suggests hints are not exactly Mass Effect cheats, and are usually just simple (but very useful) tips on how you can unlock secret level, features, find hidden areas and such. Hopefully these will make playing Mass Effect even more entertaining.
Achievements
Complete each of the following achievements below to get the allotted gamerscore.
AI Hacking Specialist (15): Use AI Hacking 75 times.
Asari Ally (20): Complete the majority of the game with the asari squad member.
Assault Rifle Expert (15): Register 150 Assault Rifle Kills.
Barrier Mastery (15): Use biotic Barrier 75 times.
Charismatic (10): Use Charm or Intimidate to resolve an impossible situation.
Completionist (25): Complete the majority of the game.
Council Legion of Merit (25): Complete Virmire.
Damping Specialist (15): Use Damping Field 75 times.
Distinguished Combat Medal (25): Complete 1 Mass Effect playthrough on the Hardcore difficulty setting.
Distinguished Service Medal (25): Complete Eden Prime.
Dog of War (25): Register 150 organic enemy kills.
Extreme Power Gamer (50): Reach 60th level with one character.
First Aid Specialist (15): Use medi-gel 150 times.
Geth Hunter (25): Register 250 Synthetic enemy kills.
Honorarium of Corporate Service (25): Complete Noveria.
Krogan Ally (20): Complete the majority of the game with the Krogan squad member.
Lift Mastery (15): Use biotic Lift 75 times.
Long Service Medal (25): Complete 2 Mass Effect Playthroughs on any setting.
Medal of Exploration (50): Land on an uncharted world.
Medal of Heroism (25): Complete Feros.
Medal of Honor (100): Complete 1 Mass Effect Playthrough on any setting.
Medal of Valor (50): Complete 1 Mass Effect playthrough on the Insanity difficulty setting.
Neural Shock Specialist (15): Use Neural Shock 75 times.
Overlord Specialist (15): Use Shield Overload 75 times.
Paragon (15): Accumulate 75% of total Paragon points.
Paramour (10): Complete any romance subplot.
Pistol Expert (10): Register 150 Pistol Kills.
Power Gamer (20): Reach 50th level with one character.
Quarian Ally (20): Complete the majority of the game with the querian squad member.
Renegade (15): Accumulate 75% of total Renegade points.
Rich (25): Exceed 1,000,000 Credits.
Sabotage Specialist (15): Use Sabotage 75 times.
Scholar (25): Find all primary Aliens: Council Races, Extinct Races and Non-Council Races codex entries.
Search and Rescue (10): Locate Dr. T’Soni in the Artemis Tau cluster.
Sentinal Ally (20): Complete the majority of the game with the Alliance sentinel squad member.
Shotgun Expert (15): Register 150 Shotgun Kills.
Singularity Mastery (15): Use biotic Singularity 75 times.
Sniper Expert (15): Register 150 Sniper Rifle Kills.
Soldier Ally (20): Complete the majority of the game with the Alliance soldier squad member.
Spectre Inductee (15): Become a Spectre.
Stasis Mastery (15): Use biotic Stasis 75 times.
Tactician (25): Complete playthrough with shield damage greater than health damage.
Throw Mastery (15): Use biotic Throw 75 times.
Turian Ally (20): Complete the majority of the game with the turian squad member.
Warp Mastery (15): Use biotic Warp 75 times.
Downloadable Content Achievements
Colonial Savior (50): Complete the Bring Down the Sky mission.
Multiple unlocks
Complete the game on Normal to unlock the secrets:
Hardcore Mode: Complete the game once
Increased Level Cap (51 - 60): Complete the game once
New Game +: Start a New Game, then select to use existing Career. You'll be playing with your older character (with all items and skills intact).
Infinite Paragon + Achievement
When you reach the Hercules System in the Attican Beta Cluster you will receive a mission to recover a "lost data pad" from the planet Eletania. Once you have found the data pad on one of the roaming local species(called a "monkey" in the game) in the mine you will be awarded approximatly 6+ paragon, save the game immediately. Once done, load the saved game and you should be able to continue to click on this monkey infinite amounts of times... I ran up my Paragon to 450+ points and, of course, received the achievement.
Infinite Renegade/Paragon
On the planet Noveria, head to the hotel bar and look for a Turian named Lorik Quinn. Accept his quest to steal the data from his office. Once you get the data, the receptionist will ask you to get Quinn to testify. Tell her you'll do it, and then go talk to Quinn. From here:
1) Tell Quinn that he should testify (top left option).
2) When he refuses, select the Charm option (top left) for Paragon points or the Intimidate (bottom left) for Renegade points and end the conversation.
3) Talk to him again, and ask about the Matriarch.
4) When he gets done talking about her, select the "Other questions" option (bottom right).
5) Now, you'll have the option to ask him to testify again (top left). He'll refuse, and you'll be able to use the Charm or Intimidate option again to gain another 24 Paragon or Renegade points.
Repeat steps 3-5 until you have all the Paragon or Renegade points you want.
Unlock Gamer Pics
Completing the game on the Hardcore and Insanity difficulties will unlock 2 special gamer pics for use on your profile.
"N7" Gamer Pic: Gain the Medal of Valor achievement
Saren Gamer Pic: Gain the Distinguished Combat Medal achievement
Class Endgame Bonus Talents
Beating the game with a specific class will allow you to give newly created characters one bonus talent.
Adept: Singularity
Infiltrator: Sniper Rifle
Vanguard: Shotgun
Infinite Credits
Here's a great way to score infinite Credits. Follow the steps below in order to do so...
1) First, fulfill the side quest involving Dr. Michel (from the Med Clinic) and her blackmailer. After the quest is complete, you'll get a discount from all of the goods she sells.
2) Start selling her all of your expensive equipment. Then, travel to the Wards Markets and talk to the merchant named Expat. You can buy all of your stuff back for cheaper than you sold it off.
3) Head back to Dr. Michel and sell off your stuff again. Repeat this process as much as you want for as much profit as you desire.
Infinite Experience
Head to the freighter on Feros (in the Zhu's Hope Colony). You'll find a computer terminal here that, when decrypted, will alert you to investigate supply shipments that have diverted course in the Voyager Cluster.
Quite simply, if you then save your game, and subsequently reload it, you'll be able to decrypt the computer again for the same information you just got. This is a slow, slow process, but it is a real way to have access to infinite experience points. If you have the patience to do it, give it a go.
Game Completion Duplication
After completing the game, you're able to restart with your character equipped with everything he had in the prior mission, as well as retaining experience, credits and more. However, there's a strange duplication anomaly present that is worth mentioning. If you take a look at your inventory, you'll notice that there are copies of what you're wearing (armor, weapons, modifications) in your inventory and equipped on you. Nifty!
Thresher Maw Tactics
Thresher Maws, which are located mostly on uninhabited or barely-inhabited planets, can be pesky foes. The best way to take care of them, as most people know, is to circle their locations as you pound them with machinegun fire and rockets from the Mako. However, Thresher Maws disappear underground and reappear near your location, and can at times reappear underneath you, instantly killing you (or leaving you dangerously close to death).
A great way to avoid this is to drive the Mako over elevated terrain as you fight these foes. Thresher Maws can only burrow underneath flat terrain, so elevated terrain is off limits to them. If you remain on elevated terrain as you fight them, they won't be able to respond to your attacks with attacks of their own.
Infinite Experience II
During your first conversation with Liara, you gain experience when you’re done speaking with her. If you reload your save after the conversation, you can actually speak to her again and get that experience one more time, over and over again. Depending on where you are in the game, this conversation is worth about a thousand experience points, so it’s quite a lucrative conversation to partake in over and over again.