I used to have the same problem when I put the doughball directly on the peel. Now, as at my neighborhood pizzerieas, I initially put the doughball on a floured board, pick up the dough to stretch it out over my knuckles and then put the dough on the (unfloured) peel. I give the peel a short, sharp jerk to make sure the dough is not sticking and, so far, it never has. Then I add the ingredients.
Basically, as long as I do any pressing down on the dough, on a separate surface and just lay the fully-stretched dough gently on the peel, I don't have a problem. Also, because I didn't flour the peel, I've virtually eliminated the problem of excess flour covering my fingers when I eat the finished pizza.