To gain unlimited Experience, at the freighter on Feros in the Zhu's Hope Colony, there is a computer terminal that, when decrypted, will alert you to investigate supply shipments that have diverted course in the Voyager Cluster. 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 process, but gives you access to infinite experience points.
If you want to repair the Mako without wasting Omni-Gel doing so, press X and opt to return to the Normandy. You'll be reinserted in a specific place when you decide to go back to the planet in question, but your Mako will be fully repaired for reinsertion.
Occasionally you might encounter a slow down on graphics and game play. If you have been playing for less than three hours and see the "Loading" text, release your controller for faster loads. If you have been playing for over three hours and the game play slows down, save and reboot your Xbox 360. This occurs because the Xbox 360 does not have an efficient way of clearing its memory for new information. Once the memory is saturated, the "lagging" game play happens. Since Mass Effect is so big and everything is unique, it uses all of the available memory.
In the ExoGeni facility, there is an objective where you have to add the correct amount of water presure to fill the gauge between the two arrows. After reaching the correct amount of water pressure enter 7, 11, 13, and then activate it to solve the puzzle.
To unlock all six ally achievements with only three playthroughs, when you start the game, focus on getting all six of your teammates. select two of them to play through the game with and keep those two until you complete the majority of the game. You will get the ally achievement for the teammate you recruited first. After getting it, replace that teammate with another one as soon as possible. After the next assignment you complete, you will then unlock the ally achievement for the second teammate.
Find a planet that has a Hazard level 1, then stand outside the Mako and repeatedly Y. Make a note of how many times you pressed [Heal]. If you do not pay attention and run out of Medi-Gel, you may die from the Hazard level.
Equip any decent sniper rifle (powerful and accurate) with High Explosive Rounds (highest level preferably). This combination will kill nearly every normal enemy you hit directly and severely damages enemies in their proximity, if not killing them as well. For fun, if you shoot the enemy's feet or the ground he is standing directly on top of, he will jettison into the air. Note: High Explosive Rounds work best only with sniper rifles since they are meant to kill with one shot. If it is used with a pistol, assault rifle, or shotgun, the weapon will overheat in around five shots (depending on the type of weapon), regardless of upgrades and decency of the gun. This will make yourself vulnerable to enemies.
In the hanger bay through C-Sec. In the right-most room in the Presidium Wards Access corridor. In the alleyway next to the market and Choras Den. In the upper market area. In the C-Sec Requisition Office. In the Traffic Control Room in C-Sec. Inside Flux, by the quasar machines in the back left. To the right of the Med Clinic entrance. At the C-Sec Academy entrance.
Four are inside Citadel Tower. In the back room of the Emporium, turn left. On the balcony of the Embassy lounge. In the rectangular room at the right of the C-Sec HQ at the embassy. Outside Citadel Tower to the left of Avina. In the Volus/Elcor office at the Embassy. Opposite of Avina, halway between the Consort Chambers and the Emporium. Outside the entrance of the Consort Chambers. Outside the Wards Access entrance, very close to the arguing Preaching Hana and C-Sec officer.
You will encounter a large worm creature during the mission about the missing Marines. To defeat it, jump right before the projectile acid the worm spits. Meanwhile, attack it with missiles (RB) and constant gunfire (RT) and it will soon fall.
To easily defeat the Thresher Maw, after it has initially launched out of the ground to drive off, stay at a relative distance and drive circles around it while firing. Due to your distance, it will not use its long-ranged attack or inflict melee damage. It will go back underground after a time or when certain amount of damage is inflicted and will change location where it pops up. Repeat the circular attack and you will get away undamaged.
Save before talking to merchant for first time when looking for certain items or armor. The merchandise is random so, if you do not get anything you want, reload the game and talk to the merchant again. This trick can be used around three times whenever enough game time has elapsed for merchants to respawn new items.
This glitch lets you have any character, for example Kaiden (normally a light armor only character), wearing armor they are not trained in (for example, Krogan heavy armor). First, have the armor you want to equip in your inventory. Make sure that you have more armor upgrades (for example, Combat Exoskeleton IX) than armors. Count from the bottom of the armor list up until you have highlighted the armor you wish to equip, and remember that number. Press X to go to the upgrades screen. The following must be executed very fast (almost instantly). Hold Y then press A, making sure not to press them simultaneously. Normally this would turn the upgrade into Omni-Gel. However, because you held Y and tapped A very quickly, the game glitches. If done correctly, you will hear the "item salvaged" sound, then a prompt screen will appear asking "Are sure you want to reduce to Omni-Gel...". Press B so you do not salvage your upgrade. You should see a lot of armor upgrades with duplicated information (just to the left of item). Once again, go to the bottom and count up to the number you found earlier. Press A to equip. The upgrades can be changed on the equipped item afterward.
This achievement requires that you locate information on all primary Alien:
Asari - Speak with Captain Anderson after the first meeting with the council. Salarians - Speak with Captain Anderson after the first meeting with the council. Turians - In the beginning of the game if you miss it, you can get it by speaking to people about Specters and Saran. Otherwise, it should appear after your first encounter with Ashley.
Rachni - Speak with the VI Avina near the Consort Chambers/Krogran Statue about the Rachni wars. Protheans - Speak with Captain Anderson and Nihlus on the Normandy at the beginning of the game in the Communications Room. This is your only chance in the game to get this codec. If you miss it, you will not be able to recover it later in the game.
Batarians - After you become a Spectre, speak with Captain Anderson about his Spectre activities at the Docking Bay. Elcor - Speak with the diplomat Calyn in the embassy. He is located at the end of the hallway to the right of the Embassy Clerk next to Udina's office. Geth - While on the mission Eden Prime you will receive this codec automatically. Hanar - Speak with the Hanar Shopkeeper at the Emporium. Keepers - Speak with the VI Avina in the northwest part of the Presidium. She is very close to the Preaching Hanar and C-Sec Turian whom are arguing. Krogan - You get this automatically by entering Choras Den. A scene will play showing the Krogran Wrex. Quarians - Speak with Garrus in the medical center after fighting the thugs. Volus - Talk to the VI Avina closest to the Embassy Clerk. You will get this by asking the VI why the Volus were the first race to get an embassy.
The best way to find the elements, minerals, and anomalies on planets that you can explore is by driving along the edges of the operational area (the red area). Drive the Mako in a circle around the area to where you can hardly see the edge of the red line to find at least two elements/minerals on each planet that can be explored. There are rare things that will not show up on your map and you will also have to drive around like this to find them. There are a couple more items than you are required to find, but it is good to go ahead and get them if you need the experience points. Also, if you say the correct things to the Asari Consort, she will give you a trinket that allows you to activate a Prothean Orb found on Eletania, or the "monkey" planet, in the Hercules system. It contains the memories of a Cro-Magnon that was observed by the Protheans. The orb will show up as an anomaly on your map, in the lower left corner.
If you are a Soldier, level up weapons to use their bonuses and no further. For example, Carnage is the shotgun's bonus. By doing this, you will have extra points for a desired weapon and points to level everything else completely out. You do not need the damage and accuracy bonus from the points as when you become a Spectre, the best of every weapon becomes unlocked for you in the Normandy or at the C-SEC requisitions office.
To gain unlimited credits, first complete the side quest with Dr. Michel and her blackmailer to get a discount from the goods she sells. Sell her all of your expensive equipment. Then, go to the Wards Markets and buy your items back from the merchant name Expat for cheaper. Repeat as desired.
To gain unlimited Paragon and Renegade points, when you get to the part of the game where Lorik Quinn is going to testify against Anoleis, speak to Lorik Quinn and convince him to testify. This will give you twenty-five Renegade poionts. Then, walk away from him, return to him, and ask him something unrelated to the case. You'll then be given the option to "Answer another question", at which point you'll be able to convince him to testify again, for another twenty-five Renegade points. Repeat as desired.
The following are the locations that the Quasar Machine's signal traces to in order:
Wards Access Corridor
Starting at the Medical Clinic, go up the elevator toward the Presidium. Take the corridor to an area where people are talking. Look at the terminal on the wall.
At Volus' Office, behind Volus.
After exiting Volus' office, turn right and go past the Emporium Shopkeeper to a back hallway. Then, turn right again. You will encounter an A.I. that threatens to blow you and itself up. After the conversation, select the A.I., and input the following code to override: TRIANGLE, SQUARE, TRIANGLE, CIRCLE, SQUARE, CIRCLE, CIRCLE. Finish before it is done Siphoning off credit to get the credits.
The fastest way of gaining the skill achievements (Lift, Warp, Sabotage, etc.) is to stand outside the Mako and use it for a target. Do each skill with your current character 75 times to get the achievements for each one. However, two things must be noted. First off, Neuroshock does damage to the Mako. When you see it begin smoking, repair it. Second, AI Hacking does not apply at all here and you must actually hack 75 AIs or hack a few repeatedly before you must destroy them. The best way to get this one is to play the mission where you must go to the Earth's moon, or "Luna", and stop the AIs in the training facility. Save the game before you go into one of the bunkers and keep hacking them until you are finished, or reload and play again.
To have an easier time hitting fast-moving enemies (such as Geth Hoppers and Geth Drones), open up the command wheel when engaging them in combat to pause the game. However, you will still be able to aim. Once you have aimed at a fast-moving enemy, exit the the command wheel. This will result in direct hits.
Adepts are biotic specialists. They start out equipped with pistols and light armor. Their upgradeable implants give them biotic powers. The powers can be used to lift or throw objects, shield the party, and disable or destroy enemies.
Using the holographic OmniTool, they can heal their party, disrupt enemy weapons or shields, decrypt security systems, and repair or modify technical equipment. They can unlock the ability to reverse enemy engineer technology and wear light armor.
Infiltrators specialize in killing or disabling enemies at long range. They are trained to use OmniTools, but focus on decryption and offensive abilities. They can learn to wear medium armor and train with pistols or sniper rifles.
Sentinels use biotic abilities and advanced healing skills to defend allies. They can only use light armor and can not receive advanced weapon training.
Soldiers start out with pistol and assault rifle training and medium combat armor. They can unlock assault training, shotgun/sniper skills, heavy combat armor, and perform first aid.
Vanguards specialize in close range attack. They train with pistols and shotsguns, and can wear medium armor.
The following upgrades are the best for any gun: Frictionless Materials X (28% heat damping, +7% damage), Kinetic Coil X (28% weapon stability, +7% damage), and Slegdehammer Rounds X (50% weapons force, + 60% poison damage, - 20 heat damping). Overall, the weapons stats you will end up with are as follows: 14% damage, +28 weapon stability, +50% weapon force, +60 poison, +8% heat damping. The poison damage also prevents shield regeneration. Also, any of the following combo of any grade is the best.
For the most powerful weapons in the game, use the following builds. For assault rifles, shotguns, and pistols, use Frictionless Materials, Scram Rail, and Inferno Rounds. Once you can get the "X" level equipment, these will be the most powerful weapons in the game. The combination should be used at any point you find these materials. For the sniper rifle, use two Frictionless Materials and High Explosive Rounds. The assault rifle will not overheat much at all, but for an assault rifle that doesn't overheat, you can use two Scram Rails and Snowblind Rounds. It is not as powerful as the first method, but nonetheless efficient.