My only tip would be to play with vehicle setups. Try upping the rear tyre pressure quite a bit, stiffening the shocks, lowering the front tyre pressure just a tad, adjust camber to allow for more oversteer, and lower your gear ratios so that all gears are mainly acceleration/tourque based, as you don't need speed, just tourque.
You may also want to try and learn to clutch kick. In a nutshell, that is where you punch in the clutch while staying on the throttle, bringing up the revs, so that when you release the clutch, your revs are built up and you have a sudden surge of power going to the wheels, giving you that hearty loss of grip that will throw your car off balance and into the slide. Just be ready to time your countersteering accordingly ;)