Problem: You choose your foundation color by matching it to the skin on your arm and it doesn't seem to blend into your face.
Solution: The skin on the inner part of your arm hasn't had the sun exposure your face has, so the color is not the same. Ask if you can test it directly on your face.
Problem: You apply foundation all over.
Solution: Skip your eyelids and ears -- they don't need makeup.
Problem: Your makeup seeps into pores and lines.
Solution: Prep skin with a primer, which fills in all the nooks and gives makeup something to grip onto. We like Benefit's POREfessional Face Primer ($31, macys.com).
Problem: Your foundation is over a year old.
Solution: Pitch it. Oxidation causes the shade to darken and it may be harboring bacteria.
Problem: Your skin appears mask-like.
Solution: If your makeup looks too heavy, it's best to wash it off and start again.
Problem: Your makeup stops at the jawline.
Solution: Be sure to brush a little foundation on the neck area. You don't want your face to be one color and your neck another.
Problem: You use a darker foundation to look tanned.
Solution: Stick with your regular shade, and warm the tone with bronzer.
Problem: Halfway through the day, you notice streaks in your foundation.
Solution: Take the time to take a quick look in the mirror and rub out errant foundation streaks before you leave the house.
Problem: Your skin is dry and flaky.
Solution: Mix a drop of moisturizer into your foundation.
Problem: No matter how hard you try, you just can't seem to achieve a perfect application.
Solution: You may have forgotten the cardinal rule of foundation -- it should enhance skin, not conceal it.
Take the guesswork out of this hot makeup trend with these simple steps.