As said above by others: Practice, and use a low powered car. 200-250 BHP/1100 kg ish is fine (stating the obvious, for CH tyres).
My personal thoughts...
Turn ABS off (if you haven't already). I see lots of lobbies where people use it, but in my opinion things feel much better when you've got used to it being off. If you've always used ABS it'll feel evil to start with, but stick with it!
Drive the car in stock form LOADS. That way when you start to tune suspension etc you'll have a reference to compare to. Get to know your ride really well. That said, trying other cars is also good, but I tend to drive my favourite 90% of the time for practice. Also, sometimes it's fun to go back to the stock settings every now and then, I've often tuned suspension and then much later found some aspects of the stock that I liked more (usually when I've set mine too stiff overall)!
Don't be afraid to try new techniques, everyone spins out or plows through a corner sometimes, but at least then you know the limits of the car, and what not to do in future. Try "doing the same thing with different methods", i.e. in a transition on a given corner, find out what you prefer... give the handbrake a tweak, or let the gas off then stomp it, or dab the brakes before/during/after steering, or try dropping a gear etc etc.
Try different lines, stick a front or rear wheel up onto the grass/rumble strip and see how it feels.
Try initiating a drift sooner or later during corner approach, change your braking points. This will effectively give you new lines, maybe you'll find one you prefer over your usual one.
If you have a really hellish session, then try driving grip for a lap or two, then gradually let a little bit of slip happen, until you're drifting again. When angry it's easy to get harsher on the controls, then you crash more, then you get angrier ....vicious circle!
Re. handling tuning.. I find the settings which make the most difference to balance (for me) are (in no particular order) toe, camber, LSD, brake balance.
Transmission is also important, since it affects rear wheel torque, hence how easily you can slip the rear tyres. When they let go obviously depends on the specifics of the corner as well as throttle and gear, but if you can get it set so things feel comfortable using the accelerator then you're well on the way. You obviously don't want the tyres instaburning the minute you touch the gas, but you equally don't want to have them refuse to let go unless the gas is 100% floored. I personally like a stable drift when I'm at 75 or 80% throttle, that way I can let off, or stomp to wide open throttle to change the car's orientation; it's nice to have options both ways.
Cheers,
Bread