Here's a tip from cookbook author, Piglet judge, and friend of FOOD52 Dorie Greenspan: when your hear your oven "tick" to signal that it's preheated, go ahead and wait a little longer. This isn't just Dorie's decades of experience talking -- she asked for advice froma Viking repairman who came to tune up her oven!
Basically, an oven cycles through temperatures that range from 25 degrees above or below the temperature you actually set -- so you might be baking your cookies at 375 degrees instead of 350. After three cycles of turning off and on, the temperature is at its most stable. So wait a while longer before slipping in that cake pan, and as always keep an eye on your baked goods with your kitchen intuition. Happy baking!