Not Using a Separate Timer
Timing is everything when you’re baking. Most ovens come with a built-in timer, but a common mistake is to rely on them. You should always have a separate timer for your baking. Or, keep an eye on your clock. You can even set a timer on your phone to keep your baked creation from burning.
Also, it is a good idea to rely on your eyes even if your timers are working perfectly. Sometimes a dish may be done a few minutes before the timer goes off, and eyeballing it can mean the difference between a perfect dish and a burned mess.