I'm just glad there's someone here who's greener than I am.
Yes, know the rules. Yes, work on your mechanics. Yes, go to games and do nothing but watch the officials - where they go, where their eyes look, how they do everything. Watch how they communicate.
And then the first time they blow the whistle and the ball goes up, it's all going to go out the window anyway, and you're going to feel like you're on the tracks trying to outrun the train.
As people here can tell you, the first day I did this (just last month), I felt totally overwhelmed. You think you know the "easy" things like how to blow the whistle. It all
looks easy, but it's not. The first day I thought I was so bad, I found this board and came on here to ask if everyone felt like that the first time out. Turns out most do.
The second day was much, much better. Had a great experienced partner, had a much better feel for what I was supposed to be doing out there. I felt like an actual official, and not somebody they just pulled out of the stands because they were a man short. Last weekend I was bummed because I
didn't have any games to do.
So good luck. Take a deep breath. Hustle, be in good position, know the rules, keep your cool, look sharp, feel sharp, be sharp, all that stuff.
And then just know that it takes time.