Back in the oooold days of the Dragon's Den of '97, there were very very few customizers out there that would share all the tricks of the trade.
This gentleman, whom I'm sure really doesn't need to be introduced, but who's site is just a frickin' wealth of 'how to' knowledge, is one everyone should visit at least once and wander around in. Just a joy.
His hints and walk-throughs on head sculpting are incredible.
Go on, go look!