well, if you have problems shooting planes from behind, you forget to use the air break ("afterburner" in the controls menu), it will let you stay longer behind.
also, having a joystick helps, otherwise massive amounts of table space is required. Played with mouse on BF1942/FH1 - possible but just killing your arm.
In FH2 1/4 of the time it depends on luck, even a middle skilled guy can take you out if he luckily dived after you did, but half of the time you can dodge it by flying really low near the ground, between the trees with drunk unpredictability.
The rest 3/4 its skill, even in stuka i find it easy to dogfight against 2 middle skilled enemy fighters. stuka breaks in mid air make opponents come into your killzone or attacking from 6 is just a piece of cake.
The best planes are the ones that have a cannon/mg shooting through propeller. guns on the wings need more calculation where to hit, so FW190 and BF109 are the best out there in terms of air superiority. without competition.
Except for a very few exceptions, I hardly find real adversaries in the air. But if I do, I always thank for a good dogfight.
A tip: don't sit in artillery when I am flying for opposing team.