Of course, the right top coat is a must.
A good base coat is very helpful, too. And yes, top and base coat do differ in important aspects!
essie top coats don't work all that well on most OPI polishes is what I experienced
Remember to go to the toilet before painting your nails.
Also, paint your nails after washing your hair! Hot water and the head massage that, fyi, you perform with your fingertips after all won't be nice to your fresh manicure.
Your manicure will hold up better on healthy nails. If they're not, change your nail polish remover. Fast!
Don't shake your nail polish bottle, your manicure might get bubbles!
Paint your nails with sufficiently lighting provided.
lacquerized has some tremendously good guides on how to paint your nails (my technique is pretty similar) and easily clean up after painting.