Drifting in the daytime levels of Sonic Unleashed seems either really clumsy1 or just plain hard. Even on the drifting course in Mazuri, it's astoundingly difficult to do it correctly (i.e. without falling off the track). I can't figure out if it's because I drift (press the shoulder button) too early, drift too late, turn too sharply or too little, or all of them combined.
At the risk of this being too broad a question, what tips, control-wise and timing-wise, should I keep in mind in order to pull off a successful and skillful Sonic Drift?
1 Apparently they refined the drifting controls for the modern Acts in Sonic Generations, as it's considerably easier to drift properly in Generations than in Unleashed. But your mileage may vary.