Ooh, good question! I always have similar problems, but here's a few ideas.
The most important thing is to use bigger landmarks to guide you towards smaller ones. The airfield may be small, but the town near it probably isn't, and if the airfield is located next to a prominent corner of the town you've got a good pointer.
Line features are always good. Lots of airfields are next to motorways or railway lines. Pick the line feature up and follow it to the airfield. Be careful about using rivers, though - they can be hard to spot from the air unless they're very big.
Try to imagine what the airfield is going to look like before you take off. Look at the runway layout, and orientate it towards the direction you'll be approaching from. Try to imagine whether the hangar buildings will obscure part of the runway, or whether you'll really be able to see that grass taxyway from the air.
All of those techniques will work for any VRP. But for an airfield, be on the lookout for lots of white crosses on the ground. These are parked aeroplanes. They always look more like crosses than aeroplanes to me unless I'm very close.
I have, on occassion, used other aircraft to locate an airfield - but that only works if the airfield has some other traffic using it, and you can spot the other traffic! Listen out on the airfield's frequency until you hear an aircraft call final. If you can see an aircraft fairly low flying in the runway direction, it's a fair bet that you'll spot the airfield 1/2 mile or so in front of him.
In general, it's grass airfields which are hard to spot. Grass airfields tend to be green. Depending on the time of year and what's growing in nearby fields, it might be the only green field around. But be careful of this one - I've mis-identified at least one airfield because there was a greener field about 1/2 mile away!
If all that doesn't help, then climb. You'd be amazed how much better the view is from 4000'. Just make sure you don't lose sight of the airfield again as you're descending back down to land!
I'm sure there are more ways that I haven't thought of or have never heard of - can't wait to read them!
FFF
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