If you are installing new wood trim or replacing old trim, the easiest way is to paint it first and then touch it up once it’s in place. However, if you are re-painting existing trim, you will need to mask the adjacent walls and/or ceiling with painter’s tape. Work from the top of the room down, painting trim closest to the ceiling and ending with the baseboards, though door and window trim may be painted at the end if so desired. For a quality job, chooses brushes that are appropriate to the size of the moulding—a 1 1/2-inch angled sash brush for narrow trim and a 2-inch brush for wider trim.
For trim that runs the length of a wall, start away from a corner by about 3 inches and paint to the corner. Change direction and paint several inches past your starting point. Continue painting the trim in sections as you did the first one, painting 3 inches toward the corner (to the previous wet edge) and then several inches out. If you had to caulk any areas before starting to paint, make sure to cover all visible caulking as you go.
Trim most often needs two coats of paint; to ensure good adhesion of the second coat, sand the trim lightly after the first has dried and rub with a tack cloth to remove the dust.
