Choose True Value EasyCare® Ultra Premium latex Paint/Primer in One in the color and finish of your choice for interior doors. For exterior doors, paint over the primer with X-O Rust Paint & Primer in One enamel. Use an angled sash brush and start with door panels or other decorative features, working from the inside of the door out. Paint the detailed or molded areas around the panels, then move on to the panels themselves. Always paint out of corners, not into them, to avoid creating paint deposits and clumps. Try not to use a heavy hand when you're painting panel-frame joints. Otherwise, the paint may end up cracking. Instead, tip off these areas with a brush that's almost dry. Paint in the direction of the wood grain.
Paint the edges. Start with the top and bottom edges. When it comes to painting the inner and outer edges, you may have a color decision to make. Some doors have a split color personality—that is, they're painted a different color on each side (for example, the back of the door is painted beige to match the beige hallway and the front is blue, to match a blue bedroom). If your door looks different coming and going, paint its inner and outer edges to match the wall that shows when the door is open against it. For example, if the door opens out to the beige hallway, paint the edges beige also, so they'll match.
When you're painting the bottom edge of a door that's still on its hinges, use a mirror to check your progress as you go.
Painting a door that's still on its hinges can result in drips and sags, especially across each panel's top molding and bottom corners. To prevent that from happening, don't overload your brush with paint. If you see any errant drips as you go, dry-brush them immediately, before they have a chance to set.
If your door is smooth, you can paint it using a mini-roller with a foam roller cover to get a smooth finish.
Watch corners for paint build-up and dab with the tips of brush bristles if necessary. If you see paint runs and drags, remove and smooth them with an upward motion of the brush. Lightly tip off the finish with a dry brush.
When you're finished, make sure the paint cures for as long possible before closing the door (at least 1 or 2 days). This will help keep the door from sticking to the jamb. You also can cover the jamb with painter’s tape to help avoid sticking.