Photo: Alex Beauchesne

I couldn't help being a little jealous. My colleague had the most flawless skin I'd ever seen. Even under the unforgiving glare of the office's harsh fluorescent bulbs, she looked perfect. I wrote off her complexion as one of those inherited blessings, like a lightning-speed metabolism or a cushy trust fund. A chance encounter in the office bathroom revealed I was wrong. I walked in on her walloping a fully loaded powder puff against her cheek. Perched on the counter was a sloppily fingerprinted bottle of CoverGirl Clean Makeup in a dusty peach shade.

I was shocked. But I was also motivated. I wanted to find out how to use foundation without looking as if I'm wearing a mask—or the wrong shade or a layer of powder; I wanted to know how to get the kind of seemingly natural perfection my work pal had. So I interrogated a dermatologist, makeup artists, and a chemist to come up with the solutions to a bunch of pressing foundation problems.

Problem: Cream, stick, liquid, powder—what's the right formula for me?

Solution: Your skin type will tell you what to use.

• If you're dry, choose a liquid, stick, or hydrating powder foundation. Liquids and sticks both have a creamy (moisturizing) consistency, and hydrating powders are blended with ingredients that deliver moisture to the skin and offer more coverage than regular pressed powders; look for clues like "compact makeup" or "foundation" on the product packaging. (Clinique Supermoisture Makeup, $23, is a good one.)
  
  
• If your skin is oily, use oil-free liquid or powder foundation. They contain powders that absorb oil, leaving you with a matte, smooth finish, says Ni'Kita Wilson, a cosmetic chemist at Cosmetech Labs in Fairfield, New Jersey. (Try Clarins Truly Matte Foundation, $34.) Mineral makeup often works well on oily skin, because the dry particles absorb moisture, says Ranella Hirsch, MD, president elect of the American Society of Cosmetic Dermatology & Aesthetic Surgery. (Try Almay Pure Blends Mineral Makeup, $12.50.) If you're prone to breakouts, use a foundation that contains salicylic acid. "It dries up the oil-producing glands that cause pimples," Hirsch says. (Try Neutrogena SkinClearing Oil-Free Makeup, $11.50.)
  
  
• If you have combination skin, strategically apply a powder foundation, which allows you to distribute more of the oil-absorbing makeup where you need it and less where you don't, without leaving visible lines (as a liquid or stick foundation would).
  
  
• If you're a novice, try a powder foundation that's right for your skin type. "It's the easiest to apply, and it disappears into the skin more easily than liquid formulas," says New York City makeup artist Mally Roncal. Next easiest is a cream foundation in a compact (which is great for dry complexions). It melts into the skin like a liquid, but because it's a solid and applied with a sponge, it's easy to control. (Try Estée Lauder Resilience Lift Extreme Ultra Firming Crème Compact Makeup SPF 15, $34.)
  
  

Problem: After a hug, it looks as if my face has come off on my husband's suit jacket.

Solution: Press a naked velvet puff to your face after applying foundation.

It will help absorb any excess and push the foundation into the skin. Or you can use a puff or brush to apply a light veil of translucent powder, which will set the foundation.