Blair says the biggest application error she sees is when people fail to pay attention to the symmetry of the mouth. "It's important to follow the natural shape of your lips -- to take your time," she says.

For pro application, draw a V shape in the center of the Cupid's Bow with liner, then round the shape on either side into a soft M. Next, draw a small horizontal line in the center of the bottom lip. Work your liner from the corner of the mouth up to the Cupid's Bow on either side of the top lip, then from the corner of the mouth down to the center on either side of the bottom lip. Starting from the same place each time helps create the symmetry you're going for. After liner, fill in your lips with lipstick using the same symmetry-wise technique. (If you're foregoing liner, skip straight to lipstick using these same steps).

With your liner and lipstick, it's important to use short, sketching strokes. "Lips are not flat or straight," explains Blair. "So if you try to draw a continuous, straight line, you won't be able to follow the natural shape of your mouth."

It may take a little practice, but this technique should yield even color and a balanced, natural-looking shape.

If you're wearing a bright color, Blair recommends using a lip brush to refine the edge of your lips -- almost like a liner. But if you're nervous about too-bold pigment, try using a lip brush to fill in the rest of your lips, as well. (Try M.A.C. Retractable Lip Brush, $24).

"Using a lip brush for application sheers out the lipstick," says King, "which can be great if you want a sheer lip." In other words, if you feel more comfortable layering your color gradually, a lip brush can be a great tool. However, if you want a full, intense lip, "It is better to apply straight from the tube."

"Applying gloss over your lipstick is a common mistake," says King. "This can cause the lipstick to bleed and transfer onto the teeth."

If you're going for more sheen on the lips, King recommends applying a lip balm first (as discussed in Rule No. 2) -- not a lip gloss. Or, instead of lipstick, opt for a highly pigmented liquid lip color, such as Nars Lip Gloss, $26.

After your lipstick is all filled in, sometimes the edge still looks a little wonky. To fix this, King suggests applying liner after your lipstick to even things out -- without going outside the edge, of course. "Often it's easier to line after lipstick application," she says, since you already have the basic shape to work with.

If you're still worried about your lipstick bleeding outside the edge, King recommends using a lip brush to apply concealer around the lip line, or doing the same with a colorless lip pencil, such as Lipstick Queen Invisible Lip Liner, $10.

Matte lipstick is classic -- and classically temperamental. Matte textures are the most drying, making exfoliation and hydration of the utmost importance. But matte lipstick also fades and rubs off more easily than other products, which means eating, kissing and even rubbing your lips together are off the table if you want to maintain a perfect pout.

"When you rub your lips together with a matte stick, it breaks the color down and ruins the Cupid's Bow shape," explains Blair. "Cream lipstick better stands up to rolling the lips."

If that all sounds a little high-maintenance for you, Smith says you can still achieve a matte finish and longer wear by dusting a translucent powder over cream lipstick.