In reply to rich pyne: I've found some great spots over the years, but half the fun is finding these places yourself - sometimes a little oasis in a sea of boulders or a tiny flat grassy platform on a sloping and inhospitable hillside.
I find possible spots by studying maps. Sometimes they turn out to be poor, but often they come up good. If you're camping low down, old settlements/shielings can make great locations - soft short grass, level platforms, stone walls for shelter and cooking out of the wind.
Torridon and Skye are generally rough and boggy but with a bit of cunning, you can find some great camp sites.
That's all I'm going to say though - start looking at maps where you'll be going and plan your route including possible overnight stop locations and back-ups if they turn out to be uncomfortable.