I am a college student about to enter graduate school, need advice.

I'm a double major in electrical engineering and physics, I'll be graduating in May and I am applying to graduate schools for Fall 2013. I am from a small town in Missouri and will likely end up at a school in California (I mention this because it's going to be a very significant change and I would appreciate any information that might be helpful). Other graduate students, what is some advice that you wish you would have had in order to be better prepared for the transition?

Also, not sure if I have provided sufficient information for a helpful response, if I need to be more specific please let me know.