1. You wait too long to buy a turkey.
2. You forget that a frozen turkey takes FOUR DAYS to thaw.
3. You don't realize that many turkeys are pre-brined.
4. You don't let your turkey come to room temperature before roasting it.
5. You don't dry the turkey really well inside the cavity and on the outside.
6. You don't salt inside the cavity.
7. You don't use a roasting rack inside your roasting pan.
8. You cook stuffing inside the bird.
9. You roast the turkey at one temperature, instead of starting it in a really hot oven and then lowering the heat.
10. You freak out about the skin browning too quickly and turn down the oven temperature.
11. You baste.
12. You don't use a real thermometer:
Often, your turkey will come with a pop-up thermometer already inserted into its breast meat. Take it out and throw it away. Pop-up thermometers are inaccurate, and many of them are set to "pop up" at 180 degrees, at which point your turkey will be overcooked.
A real meat thermometer is essential, because it tells you the exact internal temperature of your bird. So, if you take its temperature and your thermometer reads 155, you know it's almost done.
If you want a digital thermometer, this one is great and only costs $15. If you're comfortable with an analog thermometer (really they're just as easy to use), try this one, $12.
13. You check the temperature at the wrong time, in the wrong place.
WHERE SHOULD YOU CHECK THE TEMPERATURE?
Your thermometer needs to be in the thickest part of the thigh. Insert the thermometer right where the thigh meets the breast, and push it in until you feel it slide into the thigh meat.