Tell me about leather tooling

I inherited leatherworking tools a long while back and I'd like to learn how to tool leather. Anything you want to say that would be helpful or would answer the following questions would be sweet.

-What are some good resources to learn from?
-How wet is the leather supposed to be? (I think I got the right moisture level near the end of this trial)
-What are the fork-looking tools for?
-How do I make my lines stay?
-How do I achieve more depth?
-How do I make the bevel line smooth and not crappy individual stamps?

Here's the test piece I did today, nothing fancy. The main problem I had was my outline disappearing, even though I went over it several times over several moisture levels with the swivel knife and then another tool.

http://i60.tinypic.com/v6t08j.jpg

Thanks guys!