Note that there are no either/or story achievements in ME:A - if you make it all the way to the end of the game, you will get all the story achievements, regardless of the factions you support and the actions you choose.
First Contact: Land on Habitat 7.
Pathfinder: Become a Pathfinder.
Initiated: Board the Tempest.
World Shaper: Enter the vault on Eos
Foothold: Establish an outpost.
Full Roster: Recruit all 6 teammates. You don't need to seek them out, they'll all join the party naturally as part of the story.
Exaltation - Rescue the Moshae
Liberation: Completed during Hunting the Archon.
Activation: Completed During The Journey to Meridian.
Family Connections: Completed During Meridian: The Journey Home.
Mission Accomplished : Beat the game.
Loyalty Mission Achievements
While it is possible to make it through the game without doing every (or any) loyalty mission, completing the mission guarantees the achievement, regardless of the choices you make during the mission itself.
Signal Tracking - Complete Peebee's Loyalty Mission
Buccaneer - Complete Drack's Loyalty Mission
Building Bridges - Complete Jaal's Loyalty Mission
Helping Hand- Complete Vetra's Loyalty Mission
Role Model - Complete Cora's Loyalty Mission
Combat & Feat Achievements
Terminator - Kill 2000 enemies. No trick to this one, just keep killing. While certain story events can reduce the overall numbers of certain enemies, most continue to respawn throughout the entirety of the game. You'll probably hit this one ust in the course of completing the main story, but if not, a quick drive through local enemy bases and Remnant ruins will get you there in no time.
Almost There: Reach level 25 (or 15 MP). Nigh impossible to beat the main game and not pop this one.
Peak Condition: Reach level 40 (or 20 in MP). This will very likely pop during the main game, unless your're really averse to sidequest. Still, those sidequest will be wiating for you even after the main story completes, and so will this achievement.
Long Distance Jump: Travel at least 30m in a single jump. You can get this on any planet with cliffs, but using biotics rather than jump jets (by equipping the vanguard profile) helps. Dash just before landing to avoid taking damage, though some cliffs (Sheartop, Mithrava, etc) are programmed to be automatic kills. I snagged this by jumping off the cliff above Promise, on Eos.
Kitted Out- make a kill with a level 5 weapon in single-player, or equip a level 10 weapon in MP. Level 5 weapons will start dropping as Ryder passes level 30, or you can craft your own at that point (remember that not every weapon needs to be researched before being developed).
Friendly Fire - Accept Peebee's invitation to the Nexus to gain a new power - a summonable Remnant VI. To get this achievement, it's not enough for Zap (the VI is named Zap) to attack every type of Remnant, you have to actively direct him to do so. Do this by summoning him,aiming at the enemy, and pressing his summon button again. You should see a little green ray flicker between you and the target, which indicates the command has been sent. Do this for every Remnant Enemy type (Architects and Abyssals excepted).
Pinpoint Shot- Hit 250 enemy weak spots while looking through a scope. Weakspots tend to be the heads of living things, and the glowing red ports on Remnant enemies.
Vanguard Surprise - All you need here is a single level in Cloak and a single level in Charge. Use one, then immediately use the other. Death from Above - Kill 100 enemies while hovering. For best results, combine this achievement hunt with weapons that you've crafted using the Aerial Performance Enhancer augmentation (it pairs particularly well with sniper rifles).
Jack of All Trades: Equip three different profile types. You can get this achievement as soon as you've spent at least 3 points in each skill category, or 6 points each in any two categories.
Fireworks: Get 100 Power Combos. Another naturally occurring win, but you can get this faster by investing in combo and combo trigger powers for you and your squad. The biotic charge is an easy and easily accessible combo detonator.
With Our Powers Combined: A good pair with the Fireworks achievement- you get this one for detonating combos set up by your teammates. Drack is a good partner for this- targets on fire are easy to spot and then pop with a Charge or a Lance.
Trapshooter- Hit 25 floating enemies with either Concussive Shot, Lance, or Incinerate. You'll need to use Pull or Singularity to get them up in the air, then use the listed attack of your choice to shoot them down.
Fastball: Hit an enemy with a Thrown enemy 25 times. Needs the Throw ability, of course. Easiest to get against the plentiful mobs of Chosen in the game- they tend to cluster up, making easy targets. If precise aim is a problem, try throwing things into Fiends.
Rough Landing: Throw an enemy into a trip mine. Go for this one when you're facing a single enemy, so that no one else trips the mine while you're setting things up.
Sucker Punch: Hit 25 floating enemies with melee attacks. Using Pull rather than Singularity makes this easier, as it'll bring your victims to you. Ironically, the biotic-friendly asari sword sometimes has trouble targeting floaters- use the omni-blade or other favored weapon for more consistent results.
Icebreaker- shatter a frozen enemy with a jump melee attack. You can freeze them with powers or cryo bullets, but the easiest method is to use the Remnant Cryo Gauntlet (you can get one in the rem-tech crate in the Eos Vault). Punch to freeze then jump & punch to shatter.
Pyrotechnics Expert: Ignite three enemies with a continuous Flamethrower attack. Needs a levelled Flamethrower power, of course, and some densely clustered enemies. Again, Chosen are ideal, but packs of charyllions or adhi or any other unshielded foe can also work. You may want to neutralize distant sharpshooters and Anointed first.
Mastermind: Kill 100 enemies with constructs. Zap counts as a construct for you, so be sure to snag the Friendly Fire achievement while going for this one. Close Combat Specialist: Get 100 melee kills. Melee is pretty powerful in ME:A, so this is no chore. The asari sword and remnant cryo gauntlet are both a ton of fun, but even the regular omni-blade is good go-to for close kills.
Medic: Revive a teammate 25 times. You can accelerate this one by bringing lower-level 'mates with you when hunting fiends (the Earn Your Badge task, with its three Ancient Eirochs, is also ideal for this). Liam in particular is good at getting knocked out by giant animals. Revive as normal, then wait for them to get stomped again.
Hang Time: Keep the NOMAD aloft for 35 seconds. You can only do this on H047-c, and only with a gamepad or controller (mouse and keyboard are not sufficient at this time, but will hopefully be patched soon). The idea is that, by using the joystick, you can keep the NOMAD's nose up in freefall, benefiting from both your jumpjets and boost jets. Set yourself on the west end of the central rift and drive east right into the rift. Keeping the thrust button down and your nose up, quickly alternate between boost and jump. You should be able to just about levitate across the entire length of the rift.
Exploration & Adventure Achievements
Alliance: Support either the Collective or the Outcasts in Kadara. Granted on completion of the quest High Noon.
Terraformer: Increase a discovered planet to 100% Viability. This is easier than it sounds- getting to 100% Viability does *not* mean having to do 100% of the Viability quests. On the contrary- it's possible to reach 100% on some planets without even activating their Vault. Vaults, Outpost, and main story missions are the quickest way to get Viability Boost, but there are more than enough sidequests to guaranteee that 100% Viabilty is never out of your reach.
All Clear: Increase all discovered planets to 100% Viability. As above.
United: Unite the Outposts against a common threat. This unlocks in the normal course of the story, if you establish all four outposts before completing the main mission. Eos is always established, of course, but you'll want to conquer the kett base on Voeld, resolve the gang war on Kadara, and give the drive core to the Elaaden krogan, and place your bases before you start your journey to Meridian.
Data Mining: Scan 100 objects. There are thousands of scannable items, so just remember to keep your scanner up in new areas (and listen for its beeps), and you'll be fine.
Craftsmanship: Make a gun or armor set with three augments. The gun will probably be more useful, and your pockets will fill with augments as you go through the game. You can also purchase them from vendors, so if you're just looking for the achievement, pick any three and then craft a Carnifex aboard the Tempest. You can even deconstruct it later to recover the augments, if you like.
APEX: Complete the multiplayer tutorial mission. Unwavering: Beat the singleplayer game on Insanity, or succesffully complete 5 Gold missions in Multiplayer. Veteran: Successfully complete a combine 25 strike team missions or multiplayer games. This achievement does not count striek teams deployed through the APEX app.
Teamwork: Create six Strike Teams or earn 25 assist medals in MP.
Top Talent: Promote a strike team to level 20. Does not seem to factor in teams promoted in the APEX app.
Explorer: Complete a combined five strike team missions and or multiplayer extractions. Again, the APEX app doesn't seem to register here.
High Performance - Unlock level 6 in all profiles, or get a Level 6 bonus stat in multiplayer.
Matchmaker: Complete three romances across all playthroughs. See our Romance Guide for tips.
Full Power: Level up one Tech Power, one Combat Power, and one Biotic Power to rank 6. Passive skills (like weapon expertise) don't count.
Cryptographer: Complete 20 remnant encryption puzzles. Many are accessible after the end of the game, but the ones in Vaults are lost when the Vault is completed. Check our Walkthrough to find each one before the doors slam shut.