Use liner on your lips as a base - Lipstick will last longer if you fill in your lips with the liner first. If you're using light lipstick, try a nude liner. Then slick your lipstick on top.
Keep lipstick off your teeth with this trick - This is a trick I learned years ago from my mom. After applying lipstick, take your index finger & pop it in your mouth, then pull it out. The excess lipstick will come off on your finger rather than your teeth.
Apply all other makeup before putting on lipstick and lip liner.
Open your mouth wide and brush the color into the corners, so that there are no unfinished edges.
Apply lipstick from the tube or by using a firm, small lipstick brush. Coat the lips evenly. Pay special attention to staying within the lips' edges.
Blot to remove any excess color and to even out the texture.
Remember to touch lips up after a meal, as lipstick easily transfers onto coffee cups, water bottles and soda cans.

Balance heavy eye makeup with a soft lip color. Wear a rich and boldly colored lipstick to complement soft eye makeup.
Chill lip liner for easier sharpening.
Give the illusion of a thicker top lip by lining its outermost edges and foregoing liner on the bottom lip.