I would suggest that before you starting playing around with the joystick curves or controls, try flying alone and see if you can hold a steady course. Tyr some manoeuvers on clouds or ground targets, don't actually shoot. just see if you can keep a target in your crosshairs.

If you can achieve that, but can't maintain steady control when shooting.......then possibly the problem lies with your technique. In your excitement to claim a kill you may be gripping the joystick too hard, over-controlling or jerking the trigger.

They are often the common mistakes.