All you have to do is focus on where the legs cross.
Uh huh huh.
When she spins to where you have a side view, whichever leg you perceive to be in front will tell your brain which way she's spinning. Since they're the same color, and there's no depth, it's really up to your brain to pick.
So focus during the side view and try to tell yourself the "front" leg is actually behind the other leg.
I tended to focus counter-clockwise at first, until I turned it around. I don't think it has anything to do with brain function. Maybe which eye is dominant.