Tone It Down
With a light touch, you can achieve an understated (and pretty) look that's entirely suited to the professional realm. It matters, though, what exactly you're applying with that light touch.
No matter how light the layer, red lipstick at work can say "I'll do anything for a raise." It's daytime, and you're looking for respect, not ogling. Sexy, experimental and ultra-trendy styles belong elsewhere.
The more professional look is a neutral, natural one, using shades of brown, taupe, nude, light pinks and soft peaches on the cheeks, lips and lids, and a mascara shade that matches your natural lashes.
Other colors can work, too, as long as the shades are light and complementary. Contrast should be low so that the entire face appears well-blended and balanced.
And since you probably work for more than an hour a day, you also want that blended, balanced face to have some staying power.