The easiest way to remember, for any car, is to look at the way the vacuum advance pulls. It is advancing. So to advance timing just rotate in that direction.

I advance to best smooth and highest rpm, then turn back slightly to eliminate ping on acceleration. Ideal advance depends on octane and altitude. The higher the value of either, the higher the advance should be. 

If you turn the distributor housing CLOCKWISE you are advancing the timing.  If you turn it COUNTERCLOCKWISE you are retarding the timing.

You have to think about it in terms of relative motion.  Remember that when the engine is running the rotor goes around counterclockwise.  When the dizzy housing is turned clockwise, the rotor reaches any reference point on the housing "earlier".

Does rotating a dizzy anti-clockwise rather than clockwise advance it?