Choose the style of molding you want for the door. Many styles of moldings and trims can be found at home improvement stores. Which you choose is a matter of personal preference and how each style will fit in with your existing decor. Studying doors with moldings may help you decide which types and styles look best on which of your luan doors.
Decide how many panels you want to make on the door with the molding. Options include one panel on the surface of the door or two panels, one above the other. Measure the total side lengths of the panels to determine how much molding you need to buy.
Remove the door from the hinges and take off the door knobs and locking mechanisms so you have the bare door to work with. Measure out the dimensions of the molding panels on the surface of the door, and mark with a pencil -- using the straightedge -- where the moldings will go. Stick masking tape over the pencil lines to provide a clear visual representation of the moldings. Stand the door up, and inspect it to make sure the moldings will be in the correct place. Make any adjustments to the tape before moving on to the actual moldings.
Measure the dimensions of the tape on the door, especially if you made modifications to the position of the tape. Mark the lengths on your molding, then cut the molding into strips of the correct length using a miter block and a wood saw.
Lay the door flat, mark where the tape is on the door, then remove the tape. Run a line of adhesive on the back of the molding, then press the molding to the surface of the door, taking care to exactly match up the mitered corners. Allow the molding to dry completely before moving the door.