Opening the oven
Leave. Your. Oven. Alone. While. You’re. Baking! You should never open the oven door in the middle of the baking process. You might think cracking the door a tiny sliver is fine, but you never know how much heat is lost through the smallest slits. Also, can you even see what’s going on inside of the oven through a tiny slit? No, you can’t.
If you absolutely need to see the baking process (for recording purposes), then just turn the oven light on and record from the outside. If your oven doesn’t have a door, well, you’re out of luck. Wait until you hear the ding before even thinking of taking a peek.