Three Must-Live-By Tips for Your 30s

For hair color: "Something that will age you prematurely is hair color that's gone off-tone," said colorist Eric Muroski. "Make sure your bright blonde hasn't gone brassy, your brilliant brunette hasn't lost its luster, and your rich red hasn't faded to orange."

For your wardrobe: "Most women in their 30s have to look fairly professional and corporate from 9 a.m. to 5 p.m. on Mondays through Fridays, so the weekends are when they can play around with fashion," said stylist Patrick Fields. "This is probably the last decade you'll have when you'll be able to get away with wearing just a bra under a sheer top, and when that sparkly, cropped tee is going to be the only accompaniment you'll need to skinny jeans and five-inch platform pumps. Take advantage of it! This is also the time to invest in good-quality wardrobe pieces that will last a long time and that you look and feel great in."

For makeup: "At this age, it's important to have a young, fun look when going out," says makeup artist Landy Dean, "and although you don't really need to be concerned with tips about things that will make you look younger, you do need to be concerned about things that will age you. Going overboard on makeup is the number-one thing that will make you appear older than you really are. Placement matters, so pops of subtle color are really important. Even more important, though, is that you anchor color with neutrals. A dark smoky eye pairs superbly with a nude lip, and likewise, a bright cherry lip is accented best by natural, neutral tones around your eyes."