Always use a paintable caulk. Wet your finger when smoothing a caulk line.
Adhesion
Light sanding or liquid de-glossing is a must when painting over a finish glossier than being applied.
Washing
Plaster or high gloss areas are usually the only areas which need washing prior to painting.
Power Washing
Hand Cleaning is preferred. Power washing mostly removes loose dirt not spider webs, heavy dirt or mold.
Rolling
It pays to use more expensive 100% lamb's wool roller covers. They spray much less and clean up easier.
Paint Choice
Always use the top grade of your brand choice. We use Benjamin Moore most of the time.
Paint Sheen
The more shinny the paint, the more imperfections it will show. About half of the paint problems can not be washed off, they must be touched up. Higher sheen paints do not touch up well.