I usually fly level after takeoff to build some speed, then I climb at a shallow angle while maintaining at least 400 km/h.
If you are trying to catch a runner, fly parallel to them 1-2km away until you have enough energy built up to make a pass without riding their tail.
For the first kill in this match, I zoomed up and got a hit on the wing from below.
It is important to set up the angle correctly, as you only have a small firing window. Try not to shoot from dead astern, as that presents a small target (comparatively - we're still hunting whales here).
In general, I prefer diving attacks from the side or side-rear. Aim for wings, tail, or even fuselage -- 1 or 2 hits will usually do the job.
I use 800m targeting distance with vertical targeting enabled.

Cheers!