This is a common problem, especially if it's humid out or your kitchen is hot.  Make sure you flour your counter pretty generously before you start rolling the dough out. As I roll, I will pick up the dough disk every few passes and turn it 90 degrees. Add more flour underneath the dough as you work if needed. Eventually the dough circle will get big enough and thin enough that you won't be able to easily pick it up, but that's ok. By that point, you should have a good amount of insurance against it sticking too much! If you try to transfer the dough to the pie plate and it's still sticking a bit, gently wiggle a dough blade under any stuck parts to lift it up.