I would just like to add what I have learned by playing this game. It's really frustrating at first. Follow this guide and it should become easier.
First off: Select Fleet Battles vs AI from the Multiplayer& Training tab.
Use these settings:
We are going to use the TIE Bomber to go for the achievement. Load it out as follows:
-Sienar Rotary Cannon
-Sienar Beam Cannon
-Sienar Reinforced Hull
-Twin Ion Engine
I'm not sure if this was just a glitch in my game, or this is common for everyone. I noticed that my team AI and the enemy AI were staying back at the Flagships (MC-75/ISD). What I did was focus on killing enemy fighters that moved forward. This kept my teams Morale at 100% and I would let the Raider do most of the heavy lifting. *I never moved further ahead than halfway and used the middle ground for cover.*
Once both of the enemy Capital ships are down, the hard part begins: Taking down the flagship.
I used the asteroid that is below the enemy flagship as cover and then popped up from behind and targeted the enemy power systems. Hold LB and RT at the same time to deal alot of damage. Once the power system is down, you can target weak points to dish out a lot of damage. Make sure that you do not your teams morale dip below 50% ( focus on only shooting enemies -preferably "AI" not "named" enemies to bring your stats bak up).
This game has many issues. I hope this works for anyone else struggling with it. I was able to get "Great Shot, Kid" as well.
May the force be with you.