One thing that hasnt been said i dont think. Traction control, ABS and all the other assists are not available, so dont go looking for them.
To be honest, i used to spin the car loads when it stepped out, just dont be rough with the car, be smooth with the wheel and the back end wont snap, or it will be easier to catch, especially in the faster cars. Also, be smooth on the throttle, dont stamp on the accelerator, and that should help a bit.
I found the easiest way to get used to controlling oversteer was to make the car step out, and try to control it. Its annoying at first, but once you get used to it then it improves your car control loads. Try taking the XR GT Turbo out and chuck it around in the car park and around the tracks, to get used to controlling oversteer. Worked for me. Another car that is nice to do this in is the RB4 or the FXR due to the 4 wheel drive systems, which makes them a lot more contollable in a slide.