Getting the right mesh density I found a pain, I can now get some nice decent shapes etc using a lot less geometry, just by practicing and using the smooth proxy mode to mirror the low poly into a smoothed poly mesh to see what the changes on the low poly does (I dont think that I could have made that sound more confusing if I tried LOL!)

Also using the sculpt poly tool helps out a bit (with the smooth function on) to get nice subtle changes, again seeing the result using the smooth proxy.

Hope this helps