Lip liner (when done correctly) is a makeup essential. Lip liner should not be seen. It can either match your lips or lip gloss/stick color. It can be applied all over the lips to make lipstick last liner, or on the perimeter of your lips to keep lipstick from feathering and give a more polished and defined look to the lips. NEVER wear a lip liner shade darker than the lipstick color you are wearing. (It was a few month fad a few years ago, but it never ever looked right.)

Clinique's lip liner application tip, which is the one I find best to explain on how to wear lip liner on the perimeter properly:

Follow "dot-dot-dash" method to ensure ease and accuracy of application: Draw two dots on upper lip's bow, a dash across bottom of lower lip, then connect all three. To extend lip colour wear, fill in lips with liner, then follow with lipstick.

Over the years I have tried many lip liners, and I seem to add a new one into my routine once in a while, but I usually stick to what works best. For me, those are nude colors that match my own lip tone.  Here are my favorite lip liners in the nude color family - which I firmly believe that everyone should have at least one of in their makeup bag.

1. L'Oreal Paris Infallible Never Fail Lip Liner in Nude ($8.99)
   This is a twist up style type of liner that smoothly lines lips and doesn't budge all day. I like to use this over my entire lip area topped with a nude or very light translucent pink gloss for a beautiful, natural nude lip.
2. Clinique Defining Liner for Lips in Berry Nude ($14.99)
   A pencil lip liner with a handy sharpener built into the cap. This liner glides on and really protects lip color from feathering.
3. MAC Lip Pencil in Subculture ($13.00)
   A pink hued nude lip pencil that is perfect to line around the lips. This one is perfect to match more pink lipcolors beautifully. I use this one a lot!
4. MAC Lip Pencil in Spice ($13.00)
   I wear this darker nude lip liner under really light colors to darken them up a bit in the fall/winter seasons. I also wear it a lot on it's own with a gloss. It is also the lip pencil I use most often and have been for years!
5. Lancome Le Lipstique in Sheer Nude ($23)
   Le Lipstique is a very creamy lip pencil lip liner. One end contains the color while the other a brush, as it is almost preferred to be worn as a lipstick base.