Work as many games as possible! You are going to make mistakes but the important thing is that you learn from them.
Read as much as you can. This board is a wonderful resource. I suggest you use it whenever you have a question. There are a lot of great rules minds on this site!
Attend a camp. While at camp, listen and ask questions.
Also, purchase the biggest gear bag you can (you are going to need it - it's true, it's true).
A little humor for my ol' buddy M&M...haven't heard from him in a while...maybe he'll come out of the woodwork too.