1. One trick to determine whether you have the right primer is to put a coat on and let it dry, then take a razor blade and very lightly mark an X in the paint. Put duct tape over the X and then pull back. If the paint sticks, you've made a good choice.
2. Add the top coat within 24 hours after the primer dries. That's when the surface is stickiest.
3. Remove painter's tape 2-3 hours after you've completed your final coat. If you leave tape on for too long, it can remove some fresh paint with it.
4. Always assume the job will require two coats; primer counts as one. A single coat won't give the full sheen or be as washable.
5. Keep in mind that a flat finish won't cover a high-gloss finish unless you sand the wall lightly or use a de-glosser first. Likewise, latex paint shouldn't cover oil-base paint unless the surface has been primed correctly.
6. Resist the temptation to go over an area that is drying as you'll only create brush marks.
7. Don't skimp on paint. A gallon should cover 350-400 square feet.
8. Be prepared to use an extra coat of paint to even out the effects of a dark-colored paint.
9. Tint your primer to the color of your top coat for better coverage.
10. Don't oversaturate. If paint drips from a roller, you have too much. Likewise, only dip the first third of your brush's bristles into paint and tap the brush lightly side-to-side inside the can to remove excess paint.
11. Avoid cleaning latex brushes in a sink that drains into a septic tank. The latex residue can cause issues.
12. Put brushes in a plastic zippered bag when you take a break so they won't dry out. You can even freeze them for longer storage.