definitely try to get 4 of the same tires.

traction circle is basically a circle, labeled braking on top, turn to the left on the right, acceleration on the bottom, and turn to the right on the left. basically the tires have a maximum amount of grip and when you go outside the circle you have exceded the maximum grip and are sliding, so basically, when you are turning, you can only turn and brake so much before you are out of the circle, same with turning and acceleration, or just braking or acceleration.
here's a pic of the traction circle on someone's data logger http://gplra.pike.nu/tractioncircle.gif

 

Get a feel for the track configuration and dont be afraid to use the entire width of the track when going in and out of a corner. If by any means you feel brake fade during a lap, dont try to run another lap, go into the pits, let the car cool down for a bit and flush the brakes to get some fresh brake fluid in the system. After each session, check your tires for wear and adjust the air pressure accordingly (also keep an eye on the cars behavior when cornering since a slight change in front/rear tire press. can help you balance the car's handling a bit).

Bring some friends to joke around(and help you with the car, and Have tons of fun!!!!

 

Ok, I'll try to get 4 of the same tires.

Won't be afraid to use the entire width of the track and def I'm gonna bring some friends with me, so they can be the official photographers hahaha.

 

I seem to recall a "lawnmower incident" that may have been a result of STABBY STAB STABBY!!
Yes, I haz pretty words. Say it with me: Squeeze and ease.

Didn't want to overload you, but if you want to know, this is a decent explanation:
http://everything2.com/index.pl?node_id=1176958

Basically....the traction circle demonstrates the amount of grip a tire has (acceleration, cornering, braking). Imagine using 100% of the braking traction...then trying to turn. You won't turn.....just start to skid the front tires. You need to use less braking in order to combine turning as well......say 70% braking and 20% corner traction....then you are safely only using 90% of the tire's grip with a little left over.

More of an advanced concept..... but knowing the basics can save your butt on the track.

 

Nah, no brakes involved in that incident. Just n00b driver + new suspension setup.