Be sure to prime first. This is an essential part of painting new drywall and there is nothing wrong with painting over an existing finish. Priming helps to prevent peeling and color inconsistencies. You can even save some paint by tinting the primer toward the color of your topcoat. In addition, use the right brush. The common perception that “a brush is a brush” is not true when it comes to painting. Use synthetic bristle brushes for latex paint because natural bristles will become wimpy if used with this type of paint. Make sure you brush has tapered edges to make it easy for you to brush straight lines.