There are a lot of changes to adjust to as you get older. Your metabolism slows down, those dreaded gray hairs pop up, and hangovers become an all-day event. When it comes to maturing, you already know what products to buy and what tips to try, but do you know what mistakes you've been making? With a few simple tweaks to your beauty routine, you'll feel and look as fresh as you did when you were in college . . . just don't attempt any tequila shots.