Mickey, I love your 2 minute talk time!
I've been subbing for 3 years now. Most of the time, I'm with Emotional Support, Learning Disabled, or Autistic children. But when I do sub in a "Regular Ed." class, my motto is,
Firm, but Fair.
As best as you can, treat every child the same. You will have your troublemakers. You can usually have them pegged in the first 15 minutes. I make eye contact with these children frequently and if necessary, walk around the classroom and stop at their desk to teach from there without singling the child out.
You will have your angels. Try to be fair to the rest of the class and don't continually ask these children for help or answers.
Try to get to the class at least one half hour to 45 minutes early to review lesson plans, go through the teachers manuals and find supplies.
Introduce yourself to the secretary (he/she is a godsend), the Principal and the other teachers in your grades. Ask them if there is anything you need to be aware of.
Keep a personal journal of the schools, classes, teachers and summaries of your days. Did the teacher leave good lesson plans? Is there a special issue in the class? Do you need extra materials?
This is very important: DO AS MUCH OF THE WORK THAT THE TEACHER LEFT YOU IN HER PLANS THAT YOU CAN!!! Nothing will get you not asked back than doing "your own thing."
And be FIRM, but FAIR!

A lot of kids think "Yea! A sub!! No work today." These are the kids that won't like you. Don't take it personally. In time they will see your fairness.
GOOD LUCK!