Chunks of lead in your enemies engine can do wonders for your kill ratio.
The faster you win the fight, the better. Use every means available to destroy your target quickly.
Practice head - on aspect shooting and you'll be better for it.
Trying to avoid the head-on is just giving the enemy a free chance to rake your plane with bullets and then gloat about it on channel 1.
Don't confuse this with ramming. That's not being a good sporting chap.