Before you put paintbrush or roller to a wall, you first want to cut in the corners. This means painting both sides of each corner starting about two brush lengths away and painting in to the corner. Use a 2- or 3-inch brush for paints; a foam brush for glazes.

Because the drying time of flat and eggshell latex paint is so short, you can cut in an entire room before filling in the walls. Semigloss or gloss latex and alkyd paints take much longer to dry but will leave a demarcation line if the walls are not filled in while the paint is still wet. For this reason, a room should be cut in one corner at a time and the wall filled in before cutting in the next corner.

If the same paint is being used for the wall and ceiling, you can cut in the ceiling-to-wall connection just as you would the corners of a room. If the ceiling is being painted a different color, paint it first and then the walls.

Whether painting a floor or a ceiling, be sure to cut in around light fixtures, outlets, windows, doors, and any other fixed items before filling in the rest of the surface with a brush or roller.