I agree with Hysteria...there are so many invaluable suggestions and guidelines in the GM chapter. I recommend a regular read-through of that chapter, for even experienced GMs. It's very useful to have a refresher, get yourself back on track and "in the zone."

For example, I like reading over that sidebar on page 288 (Fun First, Rules Second) or page 304 of the AoR CRB (Play How You Want to Play!): I want to be sure that I am letting the players add their creative ideas while maintaining my ability to reign things in. Remembering that this is a collaborative game is paramount for me.

Secondly, reminders on how to handle thing like table talk, weird group dynamics, dice pool interpretation, fear checks, between-session stuff, character motivations, pacing...even the occasional "optional rule"...I just can't recommend it highly enough. It's less than 40 pages, with lots of pretty pictures. Give it a read once a month or so and it will stand you in good stead.