I think basics have already been covered, but a few minor things that will make your life on set easier;
-always tell the 1st A.C. if you need to leave the camera. You don't want to reappear on set with a cup of coffee to find a disgruntled first who wasn't able to get something vital because he had to stay with the camera himself.
-When switching lenses, or anything else on the camera, call out a confirmation when he hands you a lens, or anything else. That way he'll know you have a steady grip on it, and when to let go. If you make that a habit, it'll be a lot harder to drop anything because both of you thought the other had it.
-Depending on the 1st A.C., don't directly touch the camera. The rule goes; Second A.C. hands it to the first, who puts it on the camera. If you get along with the first fine, you can sometimes make an exeption, but it's best to stay in your designated area at first, make sure the trust is built up before you do anything that could make him nervous.
-If the 1st asks you for something, repeat it back so he's sure you heard it and got it right. Little things like that will show you're serious about the job, and will help you gain respect and trust faster.
About the slate; depending on the shoot, you might be in charge of loading, and you might be away loading mags at times when the slate needs to be done. try to set the slate right as soon as you can, and make sure the back-up man for the slate knows where to find it, and that you've left the set. That way nobody will get nervous when you're not around when it's time to nail the shot.
Oh, and buy the book, it's worth its money ;)