Dont waste your money on dvd's etc. Everything you need is on the net with a little google help, youtube has some good sculpting vids up too. The Minimaker link has some good pics in.
Tips
Make sure your armature is the right size and correctly proportioned.
Dont get frustrated and try to do too much in one go.
Have plenty source material to refer to as you sculpt.
Lots and lots of practice.
Feel free to post some pics of ongoing sculpts in the forum,
http://forum-of-doom.com/index.php?board=30.0,and plenty of us will try to help out. Already plenty threads there with wip sculpts you should find helpful. Anything specific dont be afraid to ask.