Make sure you do not ignore the dog fighting missions, there are plenty of achievements to be unlocked by working your way through them.
Dogfighting
When dogfighting, it is sometimes a good idea to retreat slightly from battle and put some distance between you are your target. It makes them easier to line-up for a full on assault.
Ground targets
Always slow down on the approach to ground targets, so as to give yourself more time to line up your sights and connect with your guns.
