Good questions, and most of them may point out things you can improve on.
...Why do you find always find yourself in a bogey's dead six for the easiest shot of the day.............just when you run out of ammo?...
This means your using up your ammo on long shots or snap shots. If you have patients and set up your kills, you can get kills with much less ammo. When you have a snap shot, you aim in front of your target, putting you in a worse position and loose angles if you don't kill him. You should be point your nose behind your target, get behind him and set up a good shot.
...Why do I never see the one that gets me?...
Mostly better Situational Awareness (SA), that come from experiance. You need to keep looking around, check your blind spots, and don't become fixated on one enemy. Use this when you attack, come in low from behind, they will never see you.
...Why do I keep attacking bombers?...
I ask myself the same thing

Just don't sit behind them on their 6 unless you are working with another pilot to distract the gunner. Head on shots are good, dive from above, or shoot and dive out.
...Why do I run out of fuel after a multi kill mission on short finals with full flap and at the wrong end of the drag curve?? ...
This sucks

...Why does everything climb/dive away from me, out turn me and only need two rounds to blow me up?...
You need to learn how to manage energy and how to turn. Find a trainer who understands how to energy fight. On the the two rounds... your enemy have learned how to get withing range and set up a shot

Hang in there, I have had problems with all these, but there are solutions.
Gunner