I use a clear base coat first, to protect it from direct contact with the colour (After a while of wearing colours, your nails can become yellow).
Applying colour is tricky and will require more than one try. Be prepared, have your nail polish remover next to you, cotton balls and a wooden stick. Oh, and a good chunk of time ahead of you.
When the base coat is dry, I apply the colour. I like OPI and Essie, because they tend to last longer. Shake the bottle. Remove excess polish from the brush, but leave enough for entire strokes. Start applying from base to top of the nail but DO NOT TOUCH the skin or the edges. Use three strokes: first in the middle of the nail, then on either sides.With colour you will need to apply a minimum of two coats. So it's okay if your first coat is thinner rather than thicker, actually it's desirable.
If you do touch the edge by mistake, don't worry about it. When all the other fingers are done and dry enough, roll some cotton from the cotton ball onto the spiky end of the wooden stick, then dip that into solvent. Next carefully rub over the areas that you want to "erase". You may have to re-do a nail or two in the beginning, don't worry about it.
After two coats, I like to apply a top coat of fast dry solution that also make the nail shine more. Otherwise, you can also use this old trick: a drop of oil on each nail when they are almost dry will dry them completely. Just dip to the tip of your finger in oil (any, even olive oil) and dab in on each nail; then rub it on gently.
I repeat myself, but applying colour is not easy. You have to do it a couple of times before you find what works for you. I found this video useful http://www.youtube.com/watch?v.....re=related