Of course it is going to be different for all grades and schools, but here are some brief words of wisdom.
1.) Don't be afraid. The kids won't eat you, although it might seem like they will, never fear. It is important to treat them as people and equals. Sometimes they are smarter than you are, they have proven that to me numerous times.
2.) While reading, it is a good idea to let the kid lead you, don't lead the child. If they get stuck on a word, let them try it a couple of times and then sound it out with them. Don't just give it to them, let them attain a sense of accomplishment, not inferiority.
3.) Be up front with your supervisor and be confident with your establishment. Be free comfortable enough to be able state concerns with him or her, and be comfortable with your surroundings. Your experience is going to be lots more fun and educational if you are honest with the teacher and are in an open, free environment.
4.) Share experiences with the class or with a friend. You will feel so much better about the class and the experience if you share it. Also, if you are having trouble with a student, faculty member, or a major problem arises the class or Betsy can help problem solve or contact appropriate authorities.
5.) Just have fun and be a kid. You'll end up teaching not only the kids but yourself too. Enjoy the class and listen to your heart. Re-live the childhood you may have thought you've lost.