Capt BK
Wouldn't claim to be expert but as with any photography lighting, framing, and technical expertise all add up to a good photograph. You will find that shutter speeds of around 250th or less are required to prevent the prop 'stopping'. At this speed handholding a long lens is not easy so best to go for as short a lens as you can (this also helps getting focus right). Of course this means the subject aircraft getting quite close so NEEDS a pilot used to formation work. Don't be tempted to get anyone flying close if they haven't done this before - there lies danger!. I practice formation flying every weekend and after 1800 hours flying feel that I am quite safe in a variety of aircraft but the safety factor is mostly knowing when to get out of the way.
We use high qual Nikon Digital (D1X) this means we can take plenty of pictures in a session and throw away the ones which don't make it.
UV filter will help as will polarising filter to deepen the sky.
The best shots are with the sun on the aircraft you are shooting but you can get quite a good effect with the sun behind. We find shoorting in a gentle turn gives a range of lighting conditions.
A typical session will involve aircraft left and right, low and high, forward and back, turns and level.
Background is important. We are not well blessed for variety in Norfolk but aim to do fields, built up areas, and water. Not all shots have to be extreme close up. A wide shot of a low aircraft over a photogenic background can be highly effective. Try and keep as much 'contrast' as possible between aircraft and background (unless you are trying to demonstrate the effectiveness of a camouflaged machine).
Best time of day is early morning or late evening when the quality of the light flatters.
Very general comment I am afraid but I hope it helps.