BioShock 2

This is just a simple boosting method to get the level achievements quicker.
1. Get a few other people who want to boost.
2. Play ADAM Grab (Not the team one)
3. Try to pick a level with at least 3 turrets (So up to 6 people may boost)
4. If you do not get a level with 3 then just have the 2 other players trade off on holding the little sister for points. (If you have 6 people.)
5. Get 2 people per turret.
6. Trade off hacking it for 10 points every 5 seconds-ish
7. Make sure everyone has Speed Hacker (Forgot what it's called) to make it go by faster.

[EDIT:] If nobody touches the little sister everybody gets the bonus points for a win, because the game results in a equal tie.

If for whatever reason, you want to boost and you don't have Speed Hacker you could always boost w/o it. Yes, it will be slower but eventually you will unlock Speed Hacker and then you're all good.

GOOD LUCK!!!

Feel free to message me if anything was not clear enough.

Play nothing but "Capture the Sister" and the territories gametype. In CTS, the enemies will run at you all the time so just camp near the sister and blow them away as they move toward you. In the territories game, each time you capture a point, you get a decent amount of adam. If you want you and a friend can boost by capturing and losing control points over and over again.

Another way to rack up adam is to get a friend and boost with him/her by hacking each others turrets.

For the boosting with 6 people its obvious you need a map with at least 3 turrets. Here is a list of maps, appropriate for boosting:
- Arcadia (3 turrets)
- Mercury Suites (4 turrets)
- Neptune's Bounty (3 turrets)
- Point Prometheus (3 turrets)
- Hephaestus (2 turrets and 1 vending machine which can be hack without taking a damage)

List of maps, not appropriate for boosting:
- Farmer's Market (2 turrets)
- Fort Frolic (2 turrets)
- Home for the Poor (2 turrets)
- Medical Pavilion (2 turrets)
- Kashmir Restaurant (2 turrets)

All DLC maps are not good for the boosting, because all of them has 2 turrets and even less (Fontaine Fisheries has 1 turret)

P.S.: Also, use trials! Some trials on high level are very easy to complete (like 5-10 seconds) and give you a 1000 ADAM

UPD: JMJimmy says on comments:
"Most of the 2nd part of the list can be boosted in the same method as Hephaestus.
Fort Frolic = machine by the rocket turret
Farmer's Market = left of the rocket turret there's a vending machine beside a set of stairs that can be hacked
Kashmir Restaurant = Upstairs bathroom has a vending machine that can be hacked through the wall
etc

A bunch of the DLC maps also have vending machines that can be easily hacked (without using freeze method). Basically any vending machine that has a flat wall on the right side of it with enough room for 2 people can be done like the Fort Frolic."

I obtained this Achievement by playing only Cival War. You get alot more Adam in this game mode even if you lose you can get 150 to 230 Adam but if you win you can get 350 to 500 Adam plus whatever trials you complete. This can level you up very fast, I hope this helps.

>> Legit Skin Job achievement solution only <<

I think that the best way to obtain this achievement legit is to play Civil War how much as you can. Survival of the Fittest is much more frustrating and less effective, Capture the Sister takes too long. Others are much more less effective.
One Civil War match takes about 5-7 minutes, and you get at least 150 ADAM for completing each (if you aren't in the winning team) or 200 ADAM (if your team win tha match) even if you don't do anything else during this time.
You can easily gain about 350-500 ADAM if your stats are good (10 ADAM per each kill, photo, hack & vials, 50 ADAM for killing streak, 5 ADAM for kill assist, 100 ADAM for Big Daddy kill and 50 ADAM for each being Big Daddy) or much more if you complete some trials (additional 75-500 ADAM for each).
I'm level 42 now and I played for about 15 hours to level up to rank 30 (+ about 2,5 hours waiting/lobby time).
Level 30 needs to gain 53.000 ADAM total.

* If you want to leave a negative vote, please tell me why, so I can fix my solution if there are any mistakes in it.