Don't countersteer all the time. If you do, then make sure that the oversteer is constant so that when you countersteer, the car won't spin out. Here's what I think of:
When I understeer, I floor the gas pedal/throttle until the car has a certain angle that I want to drift that corner.
When I oversteer, I countersteer a little bit and then I modulate on the throttle to keep the car oversteering. If it oversteers, countersteer more.
Also, it takes practice. LOTS of practice.
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