Sure, powersliding or throttle-oversteer is probably the number one element of drifting, but for what is generally called drifting these days you need to also enter the turn sideways, not just start sliding when you get on the throttle (generally at or a lil before the turns apex).

Generally people will come at a turn with a LOT of speed and tap the brakes a little whle cutting the wheel toward the turn to make the rear end swing out. Emergency brake and scandinavian flick (initially turning the wheel the wrong way to loosen the rear end and then cutting the wheel back and powering through the slide) are a couple other ways though. Getting from this point to where you can accelerate out of the turn sideways is the hard part.

If your car is setup for it, you can sometimes carry the car sideways all the way to the apex just with the inertia. This is generally the traditional way, but some drivers prefer using the emergency brake (e-brake) or even throttle to balance the car toward the apex. Using throttle is difficult to do though without adding speed, but works great if you're running a late apex line and you can get on the gas early to shoot through.

Hope I didn't overwhelm you with terms there,
Cheers

-sean