I posted this in a private forum which proved to be of some use, I am re-posting it here in case it can help anyone else...
Three "mechanical" tips to improving your fighter gunnery that you may not think about...
1) When you are controlling the stick and firing at the same time just the act of squeezing the trigger, if done too hard or if your stick grip is too loose, can throw your shot off. You tend to squeeze your whole hand to fire, not just that one finger, this will mess up your aim. When I get into a fight I'll first get a really good grip on the stick, not hard just firm, then gently lay my trigger finger on the fire button at the ready.
2) Over controlling with rudder. This is a common mistake people with pedals make, I do it myself sometimes. You'll over-control with rudder to alter the nose pitch for a deflection angle, but in doing so you get too far out of plane with the bandit or off the natural deflection angle. Then if you try to correct at the last instant you'll get a nose-bounce effect. Try to avoid anything but very fine rudder control when going to guns.
3) Be very careful with your head. When my aim is off it's usually me tilting my head or even leaning my torso into the angle of my plane's turn. This distorts your visual perception of the deflection angle. So, be very conscious of keeping your head and neck perfectly straight while maneuvering for a deflection shot
