Drink Lots of Water
You've heard it before, but I'll say it again: drink up! Your skin is the first place to show the effects of dehydration. If you're not drinking enough water (aim for half your body weight in ounces per day), your skin will look dull and sallow. You'll even look older and be more prone to breakouts. Pro tip: add lemon to your water to raise the pH and boost hydration even more.