ok, first, don't use AT.
Secondly, don't use a car with over 550ps. Any more than that and the car gets too "unmanagable" with on/off throttle changes.
Get into the habit of "tapping" the throttle button... give it a bootful to get the tail out, then just as the car is at the point where it might do a 180 turn, back-off FOR A FRACTION OF A SECOND, then "tap" the throttle again... and again... and again, in quick succession. All this time your steering from full lock (either way, depending if it's a right/left-hand corner) to center, to full-lock again, balacing the steering inputs with the throttle tapping. Use the brakes ONLY to keep the tail-out attitude in control.
When you've mastered a good drift be it at Trial mountain, or the Big loop at Complex String, then you can get into using the handbrake to start the slide waaaaaay back from the corner...