What helped me was going into the TA and practicing turning the different airplanes right at the stall limit. I would just take a Hellcat, did it with many different types but as an example, and turn it 30 times in a row, using flaps/not using them, using the vertical, letting out the wheels, and most of all using my different views as I did it.
Round and round and round. Easing off and on the gas, taking snap shots. I even did it with IL2s. I'd go into the arena and just practice turns.
And you find out a few things, at least I did. That trim is very important, "I dont like combat trim when turn fighting", and slight reverse rudder helps keep your nose up. And not that I became a great turn fighter but it did help me a lot. My biggest problem was keeping awareness while turning and using my views correctly.
I recommend doing that, and also spending a tour in pure turn fighters to get your skills and confidence levels up. I'd also recommend getting with a trainer because thats where I got that turn drill from.
When I first starting flying fighters I never even looked at my score for 4 months. Forget score. Your best fights just might be ones you lose.