Remove any hardware, such as a doorknob, deadbolt and knocker, from the door.
Apply a generous coat of paint stripper to the door using a foam brush. The paint will eventually begin to bubble up as it separates from the wood.
Scrape the separated paint from the door with a putty knife.
Repeat the stripping process until most of the paint is removed and you are down to bare wood. This may take two or three applications to achieve.
Sand the crevices to remove any small bits of paint that remain.
Sand the entire door using an orbital sander until it is very smooth. Start with medium-grit sandpaper and end with extra-fine.
Fill the hole from the door knocker as well as any other dents and imperfections with paintable wood filler. Allow it to dry completely and lightly sand with fine-grit sandpaper until smooth.
Wipe away saw dust and debris with a damp cloth. Allow the door to dry completely.
Spray on one coat of spray primer and allow it to dry completely.
Brush on two coats of interior paint, allowing each coat to dry completely between applications.
Wipe on a coat of polyurethane using a clean, dry cloth. Allow to dry according to manufacturer instructions.
Screw the first half of the cleat to the back of the headboard with the thinnest point of the beveled edge away from the back of the headboard and pointing down. Center the cleat about two inches down from what will become the top of the headboard. The top of the cleat should not be easily visible once it is hung on the wall.
Attach the strip of lumber on the back of the headboard about six inches from the bottom.
Determine where the top of the headboard will be located on the wall. Obtain this by measuring from the floor to the top of your mattress and adding this number to the width of the door. Most doors are 30 to 36 inches wide. Add an additional two inches for clearance between the top of the mattress and the bottom of the headboard. Draw a horizontal line on the wall that corresponds with this final measurement.
Measure from the top of the headboard to the bottom of the attached french cleat. Make a second horizontal line on the wall, below the first line, that corresponds to this measurement. This line represents where the beveled edge on the wall cleat will begin.
Attach the second half of the french cleat to the wall with the thinnest point of the beveled edge away from the wall and pointing up. For the strongest hold, locate and drill directly into wall studs.
Hang the door on the wall, making sure both parts of the cleat line up evenly with each other.