If your tail steps out, throttle is the main way to bring it back. Unfortunately for most people, when they start to spin, their first reaction is to let off the gas and hit the brakes. This is the worst possible thing to do, as that shifts the weight distribution of the car forward, removing any bit of traction you had. Instead, you should mash on the gas while keeping your tires pointed in the direction in which you intend to go. That should gain you back your tail end traction.

To step out your rear, let off the gas rapidly and apply a little brake if neccesary.