i think you just hafta learn yourself. It seems everyone is giving a different method of doing it based on how they learned to do it. Just to add to the method pool, I did it in my impreza lm by first knowing the speed and exact point to start the 360, then mashing the ebrake and gas at the same time until I start to spin at the desired speed. I've not really tried it, but I don't see any reason why I couldn't do two 360's before a corner using this method.
A little advice: Unless ur on sims, I think its really important to have the rear tires spinning at some speed at all times throughout the drift. I found that if I just use the ebrake to start the drift, and once I get the car into a 180 position and the rear tires are not spinning, its really hard for the car to start them spinning again at the end of the drift if they didn't have some rotation to begin with.