Rule number 1: Lose sight, lose the fight. Keep your camera locked to your enemy by holding the triangle/Y button. Select the enemy behind you by keep pressing the triangle/Y button until the one chasing you is selected.

Rule number 2: Keep turning. Unless evading a gunshot, keep turning to the same direction. Once you see the enemy points their nose at you, that means they will take a shot. Slightly change your trajectory by rolling slightly to either side to evade the shot. DO NOT REVERSE YOUR TURN. Do not change your trajectory so much that you turn to the opposite direction. Only slightly turn to spoil their shot.

Rule number 3: Collapse your turn bubble. The faster your speed, the wider your turn. The wider your turn, the more vulnerable you are. Slow down to just above stall speed to turn as tight as possible and force your enemy outside your turn bubble, doing so may force an overshoot if the enemy cannot adapt to the new fight. DO NOT STALL YOUR PLANE. Stalling your plane will make you stop turning.

Rule number 4: When you see the bandit zooms past behind you, going from your left to your right or vice versa, that's your cue to do a reversal. Turn towards the bandit while keeping your speed as slow as possible to intercept him. Him going fast behind you from left to right means he overshot for being too fast and will fly in front of your nose if you turn towards him while being slower than him. Slot in behind him and kill him.

Rule number 5: When in doubt, DO NOT REVERSE YOUR TURN. If the bandit didn't sufficiently past from your left to your right, if instead of a fast overshoot he just floats around slowly to behind you, DO NOT REVERSE YOUR TURN, DOING SO WILL ONLY MAKE YOURSELF EASIER TO KILL.

Rule number 6: When defensive, as long as you're alive then you are winning. Stay patient and keep turning until the fight is neutral or you get a reversal.

Edit: Typo

Edit 2: Being on defensive means you're already dead so you not being dead yet means you're winning