[Avimimus]

I'd say: Make sure you never need to get the best out of your aircraft

Basic rules for flying:
- Don't panic, stay relaxed
- Only attack if you have equal or greater numbers
- Never attack a bomber from the rear (unless the gunners haven't had time to find you)
- Make sure you know the number of enemies and try to keep altitude so you can escape
- It is a good thing to go home with plenty of ammo remaining (never know what you might meet)
- Negotiate each maneuver with your airplane and trust it. It deserves respect and will not always do your bidding
- Be conservative enough in your flying to avoid the ground (one can lose controls in a dive or enter into a spine while flying low)
- Don't expect to be an ace, just try to survive each encounter
- Be patient, wait, watch, climb, retreat, refuel, repeat

There are also some good guides for campaign flying (different skills from Dogfight or QMB) around...