This is something that wasn't obvious to me in the beginning, but I found that if I'm moving the blade before the stroke, the risk of nicks/cuts is much, much lower. Static friction is your enemy! Also, I found that the easiest ATG strokes are done on my sideburn areas. It's flat and also easy to judge the angle of the razor there. It's also advantageous at this stage to learn to shave with both hands if you feel capable.

Pretty soon you will be slicing your strop(s) more than your face.