Summarize:

Move an oven rack to the bottom third of the oven. You'll probably need to move the middle rack higher in your oven or remove it so the turkey breast fits. If you remove an oven rack, set it aside until you're finished roasting the turkey breast. Preheating the oven to a higher temperature than you cook the turkey at will help its skin crisp.
Preheat the oven to 450F (232C) and adjust the oven racks.