proper car control takes years to master, I would suggest anything that offers cheap 1/2 day car control sessions, especially those associated with motoring groups, not to be worth much. Start young and practice. Or if its too late to start young, then practice.
Finish the car, then go use it in a safe and controlled environment. join a car club and participate, choose one that has a strong competition side and compete. Dont try and win on your first outing, that will probably either damage your car or you and incur the wrath of your club mates. try Motorkanah, as stated above its an excellent skill based/building event which teaches car control, but more importantly car reaction. Most drivers do not know what a sliding car feels like until its too late, in this environment if the cars not sliding your not doing it right, and thus you learn not only how a car reacts but what to do when it does it!
Try sprints as well, these are single car timed events on a circuit. much faster, but there is runoff. Most clubs will not allow you to be too silly, there are rules and behaviour standards, these will be enforced as the clubs cant afford accidents etc as event insurances, licencing and venue hire is expensive enough, and many people have been doing it for years so much knowledge on car control and setup. many run driver 'training' sessions for novices. Try hillclimbs, ost's, kanah crosses etc. Do not try it on the road!
Most of all respect yourself and your car, as well as everyone else out there at the same time and have fun, learn at your pace and dont get willyy, or you will damage your car or yourself!
Cheers,
JP