Supreme Commander 2

This method will take about 2 hours to do and will get you the SHARP SHOOTER and BUILD MASTER achievement.
Find a Friend to boost with, then begin a Private skirmish with no AI's on the Setons Gultch 4v4 Map. Each side of the map has a ton of mass extractors and a small bridge in the middle to get between both islands. Both of you need to play as Cybran, I will explain why later in the solution.

Have you and your partner begin by building up your economies. Focus on mass and power and try to get the the Mass Conversion upgrade under your Structure tab (its near the middle, sort of in the middle) Once you have a booming economy both of you need to start building a wall of anti air turrets near the beginning of each section of the bridge. (where the skinny part begins to get wider on each side) then build Air factories....lots of them. and Build the basic air unit and set each factory to repeat build. Then set all of the way point of each factory to the other persons turrets. From here just sit back, watch a movie, go for a jog, take a nap, whatever suits you. Just make sure your economy can sustain the production of so many units before you leave. If your economy can't handle the production of so many units, then the factories will stop building units to accommodate for the low income of resources. Each time you make a unit it will count towards the builder cheev, and each time you kill a unit, it will count towards the kill cheev.

DON'T upgrade anything that will slow down the process of killing/building. You should, however, upgrade everything on your acu (so it doesnt die), upgrade the flight speed of the aircraft and ONLY that, upgrade your mass and energy income, and upgrade the damage of your turrets and THATS IT.

To put things into perspective I wrote down some numbers dealing with what I had when I achieved an economy that produced the maximum amount of units per second, and still keep them coming.

I had:
35 AA turrets
32 Air Factories
68 Power plants (conversion included in the plants)
0 Mass extractors (Didnt need them because of the conversion on the power plants)
7 engineers (To clean up the pile of dead planes at the turrets)

I Did the math for having all of this too:
22 planes were produced every 12 seconds = 110 planes per min or 5000 kills/builds every 45-50 minutes roughly.

So overall, if you follow this and get within the ballpark of what I did, it will only take 2 - 2 1/2 for the both of you to get these achievements.
The trick to it all is finding a balanced economy, while still producing the maximum number of planes per second possible. Once you do that it's smooth sailing to an easy 50 GS

****ALSO NOTE*****
I forgot to mention that you have a 200 unit limit. This includes building in there too. So don't go overboard with power, turrets, etc because it will only cause you to have to wait longer for the achievement to pop. The number of buildings I had (listed above) was all I had so I could just focus on building planes.

The last thing to remember is that the ACHIEVEMENT WILL NOT POP DURING THE GAME. It will pop once you end the game by killing the other ones acu/base. So once you feel like you've done enough, have one person take the other one out and look at the kills at the end of the game to accommodate for how close you both are.

>>>>>>>>If you have any questions, comments, concerns, or see a problem in the solution just message me on xboxlive or on TA.
Good Luck!

THE SETUP:

From the main menu select: SKIRMISH

Map: Fields of Isis

Game Type: ASSASSINATION

Rush Timer: OFF

PLAYER 1 (which is you)
Team: 1
Faction: UEF
Color: Pick your favorite color
Starting Position: A (use to select starting position if necessary)

PLAYER 2 (computer player)
Team: 2
Faction: UEF
Color: Pick the color you hate most
AI Profile: Hard
Starting Position: C (use to select starting position if necessary)

THE METHOD:

The method is explained in the video below.

The achievements will ONLY unlock after you have COMPLETED the match

ACHIEVEMENTS