Advice for first college experience?

[jdw3018]

It's not a big deal at all (evidenced by the fact that I've been selected to do this), but I'm filling in at a local D-II University scrimmage tomorrow morning. One of my goals is eventually to work my way into some college officiating, but I'm not there yet, and have no false assumptions that this means anything other than I'm friendly, do a good job at the HS games I do, and available.

I do, however, want to do as good a job as possible for them tomorrow, so I'm open to any and all advice from those who have any experience switching between HS and NCAA officiating. Any "swing thoughts" I should have in my head? Any easy review of rules differences other than the back of the NFHS manual? Anything else?

Most of all, I'm going to enjoy it and call the best game I can, but I'm excited just to experience this level of game play and see how I stack up, so I want to be as prepared as possible...