A few months...hmmmm... set convergence of all guns to anywhere from 350-400 yards.
Go into the Training Arena (TA) turn on lead compute sights (Control-Tab) then Tab through to your target. The+'s are bullet impact points. The +'s show you just how much you really need to aim to get a shot in.
Concentrate on saddling up at the distance you have your gun convergence set to. Spend you time get into range. Once your there and own the guy THEN concentrate on the shot.
Most people have a tendency to pull the stick back when they take a shot. This will pull your aiming pipper (and guns) off target. Just before you shoot conciously ease your grip on the trigger then shoot. If you suspect you might be having this problem just go into the TA and once you get into the plane you can bring up a target to shoot at. Shoot at it and see if you can hold on the spot you aimed at. Here's how you set up the target....
Using . (dot) commands hit your text buffer (/) and type .target 200 and hit enter.
This brings up a target at 200 yards distance. If you want 300 yards then type .target 300.
The target can only be seen when you turn and face North.
You can zoom the taget by hitting your Z key. Then use the brackets to zoom in or out.
Turning off the target is .target 0 (zero).
For your purposes you type .target 350 or 400 and go shoot it.
For most newer folks the hardest part of the shot is saddling up. 90% of the time it's because you lose sight in the fight. If you have trouble saddling up or lose sight come over to the TA and get with a Trainer.
Hope this helps.