Are you using a controller or joystick? The mouse controls are simply terrible for me, the deadzone seems to be set way too high, plus it was just meant to be played with a stick of some sort.
I also realized that all the units have no ai. They all just fly/walk their pre-determined paths, shooting whatever's in front of them. The game actually has some really brilliant level design, cleverly forcing you into killzones and having ties spawn behind you.
Once you realize that a lot of the missions are a lot simpler. But here's some tips I can give you.
Never attack walkers from the front. Just fly over them and come in from the rear or sides.
All fighters and bombers fly the same paths. A lot of missions will have them spawn behind you during certain moments, usually all you have to do is fly to the side to get out of their way. A lot of times they'll spawn behind each other meaning it's sometimes not a good idea to attack from behind. Flanking them is almost always the best option.
All turbo lasers and missile turrets can be killed by 2 blasts from all four of the x wings blasters at once. So change the x wings guns to all linked, then point at a turret while in range, fire twice and get out of the way.
