Not much to add to the advice given above, just an anecdote from my own experience to back it up!
When I first started student cross countries from my home base of Netherthorpe, I always had diffuculty spotting the airfield (field being the operative word here - in amongst lots of other, mostly bigger, fields!). The trick, when I discovered it, was as noted above - stop concentrating on the field itself and look for more obvious landmarks (like the large wood and the quarry).
Kirsty - not sure I can agree with you - identifying obvious features to right or left or on track is surely an effective method? I would consider feature crawling to be zig zagging on and off intended course to overfly said features.
p.s. Or maybe I'm just rubbish at navigation!