There are a few tricks to it.
Let your subconscious focus on the size of the car, depending on the corner you're going into or hairpin you're sliding across.
Focus on the turn - it's good to memorise a track. Knowing the next and current corner's depth and length and what speeds are applicable. Before coming out of your current drift (about 95% into it), think about your next turn and how you need to approach it, and at relatively what speed. Hug the corners as closely as possible, or as closely as you feel comfortable.
Hand/Emergency brake application: never hold it down for too long. I use it in quick, rapid succession. Your car will undoubtedly spin out, or stop dead, if too much E-brake is applied, or is held for too long. Tap E-brake just enough to get your car to stay sideways without fishtailing.
Be smart, not cocky: linking your turns together for more points and to keep the multiplier climbing is obviously very important, but slamming into a wall and losing points as a result, is not. It's good to now and again take a small risk, but silly to risk a lot of points for the sake of wanting more than you can handle (given the situation you're in).
Know the car: it's relatively easy to take a car, drive fast, yank the E-brake and score points - however, it's a lot easier when you know your car. Practice enough with one specific car. Know its limts, its strengths and weaknesses. You need almost reach a point where you can "feel" exactly how the car's handling; when to push it and when to hold it back just a little more.
Hope this helps