Congratulations on your new position!  A good teacher's aid is like gold to the teacher.  These are some of the things I liked best in the teacher's aid I had when teaching.  

Treat the students and parents with respect.
Help pass out materials.
Don't be afraid to get your hand dirty.
Look for potential behavior problems and stop them before they even start.
Stand or sit closer to students who might cause a problem.
Help students who are struggling.
Offer to read stories aloud, so the teacher can attend to other problems.  There is an art to reading aloud to students.  Below are some websites you can check out.
Know the rules and follow them.  Kids learn best by example.
Ask the teacher what she would like you to do as a daily routine - pick up students, collect homework, assist students, etc.
Enjoy the experience!

I'm sure you are going to do great.  Good luck!