It's pretty easy, well most of the time. The cars handling is quite sluggish and heavy, so it's about your weight transfer when sliding round corners, that's what will make the difference between a good drift and spinning out or crashing.
You should approach a corner at a reasonably fast speed (but a controllable one, not supersonic), then release the accelerator (RT) and tap the handbrake (RB) while turning in the desired direction. Doing this will cause the weight in the car to shift in the opposite direction, which in turn causes you to slide. But in order to avoid a spinout you need to counter the weight shift, so once your about midway through the corner, you need to turn the wheels in the other direction to keep the car pointing where you want (this is what takes practise, and it usually involves moving the stick left and right alot - since the car is still spinning you can't simply turn the wheel and expect it to go where you want). By this point you should be using full throttle to finish the drift.
It sounds complicated but it's really not.
- Throttle
- Turn
- Release throttle and keep the car in control
- Align the car to the direction you want
- When your lined up give full throttle.
- Practise
There's many ways to do, there isn't one "technique".
Hope it helps, search some YouTube videos for reference.
This post has been edited by SmC12 on Friday, Apr 13 2012, 01:53 
Grand Theft Auto IV
