Foundation helps your makeup go on evenly and can help your makeup stay on longer. Skipping it can subtract these benefits as well as - gasp! - age you. The horror!

We've all seen her: the poor woman whose skin color changes, dramatically, at her jawline. she's just wearing the wrong shade of foundation, and it's easy to avoid being her. Choose a couple shades close to your skin tone, apply and blend slightly at you jawline, then check yourself out in both natural light and in "office" light. Wear the one that blends the best.

if you're using a spatula to apply your foundation, put it down and back slowly away from your mirror. Use a soft sponge instead... and use a little less. You don't need a lot, really!

There are loads of foundations on the market, so it can be daunting to choose the right one, even after you've found the shade that's right for you. The key is to choose one for your skin type: oily (like me), normal, sensitive (also like me), or dry.

Remember the lady with the two-tone skin at her jawline? Another way to avoid this ... umm ... look ... is to be sure to blend well at your jaw and down your neck just a smidge.

It's tempting to dip you fingers into the jar and apply your foundation with your fingertips, but don't. Your fingers can carry germs, and they don't apply foundation as evenly as a sponge or brush.

First comes moisturizer. Once that's dry, it's time for primer (if you want one). Once THAT'S ready, it's time for foundation. Then concealer, once your foundation is dry. The key is to use them in the right order, and to make sure the last layer is dry before you apply the next.

I confess: I have made each of these mistakes at least once in my life. Which of these foundation faux pas have you made?