if you hit someone you will see hit sprites on the plane your shooting at, as Innominate suggested go offline and shoot down the drones for a bit try different angles of attack etc
And a good tip is dont pull the trigger untell you are at least d300 away from nme,
So get good at flying and learn your ACM so that you can get real close to the nme as you cant miss something filling your windshield
Another tip is use the
.target xxx
command, this will make a target appear to the north at a set distance, so if you type:
.target 500
a target will appear d500 away to the north, .target 0 to make it go away.
with this you will be able to see how much the bullets drop over distance, so that you willl be able to aim better to allow for the tragectories of the differing types of ammo that the planes carry, ie 30mm cannon drops off very quick so you need to aim higher, 50 cal mg has a very flay tragectory so drop off isn't so much of an issue.
hope helps a bit