Read the rulebook. Not like you're studying for a final.
Read the New To Racing botto sticky. Great stuff in there.
Go through all of CDR's blog videos. They are internet gold.
I ride (and sometimes race) with Juniors a lot. I'll put them into two categories.
The ones that are cocky, know everything, ride stupid, and are a general pain in the ass.
The ones that are eager to learn, ask good questions, and follow through on advice.
Be the latter. And welcome.