Make sure you've got enough flour on your surface as you are rolling out. You don't need to drown it. Keep your dough moving as you roll it out, to make sure it isn't sticking. I like to flip it a few times if needed. Make sure that you also square off your dough as you are rolling it out. I use a bench scraper to make sure my dough is even as I am rolling it out, so that it gets as close to a rectangle as possible.