“I don’t know but I’ll find out” is okay as long as you don’t have to use it too often.
There is no money in enemies for TA’s. Do not provoke the kids.
Observe other TA’s teaching your course and borrow their good stuff.
Invite another TA to observe your class for constructive criticism.
Project confidence!
Realise that most of the kids couldn’t care less about what you have to say and are just trying to get by with a decent grade with minimal effort.
If things ever get out of hand, call time-out, loudly.
Do not get emotionally or relationally attached to any of the charges.
Grade fairly, toughly, as objectively as possible and consistently.
It’s okay to be a bit more laid back during office hours, but not too much.
Don’t try to make friends with them or act their age.
No dead air. Make sure you fill the time and are extra organised. Over-prepare the first time for about three times as much time as time you have in class. Make time for questions and question them for understanding. Tell them what you are going to say, say it (with numerous relevant examples) and then tell them what you told them. Repeat for the next point, etc. They’re not going to catch it the first time.
Respect the kids, their questions and ideas without necessarily agreeing with them all the time. (Don’t ever be a jerk.)
Never let a kid hi-jack your class. Know what it takes to steer class back on topic.
Don’t be afraid to take a troublemaker aside after class and have a little talk in private.
Know your stuff
Know your stuff
Know your stuff
Have good notes
Should something bad ever happen, get your story straight and try to find corroborating witnesses
If you ever get in trouble with the kids and it goes to the administration, find out what they think you did wrong, cooperate and address their issues.