Measure the width of the closet along the back wall.
Cut the 2-inch and 4-inch-wide lumber 1/4-inch less than the width of the closet so that you have a narrow and a wide board.
Sand the boards. Remove dust with a tack cloth.
Apply two coats of varnish. Allow the boards to dry overnight between coats.
Lay the 2-inch-wide board horizontally with the face grain up on a flat work surface. Wood boards have three main surfaces: end grain, or the blunt cut end of the wood fibers; side grain, which is the thinner length of the board; and face grain, which is the main surface of the board that displays the length of the wood fibers. If the board is 2 feet long the end grain measures 1-by-2 inches, the side grain 1-by-24 inches and the end grain measures 2-by-24 inches
Measure and mark 2 inches from the left side of the board. Repeat on the right. Draw a vertical line across the face grain at the 2-inch marks.
Line up a 2-inch L-bracket along the inside of the left line; align the angled section of the bracket with the bottom of the board. Fasten the bracket in place with 1/2-inch screws. Align a second bracket with the vertical line on the right and fasten it to the board.
Repeat Steps 5 through 7 with the other board.
Hold the toe of a shoe against the wall to determine the desired placement of the rack; you can place the rack at any height from the ceiling to the floor for storage in the bottom or top of a small closet. Consider placing the rack about 6 inches above the closet floor to allow space for additional storage beneath the shoes. Use a level to draw a straight line at this point.
Line up the wide board with the line on the closet wall; the face grain of the wood will face up and the edge grain will press against the wall. Insert a pencil into the bracket screw holes and mark each on the wall. Drill pilot holes at each mark.
Hold the wide board in place and fasten it to the wall by driving #8 flat head, countersunk screws through the bracket and into each pilot hole.
Repeat Steps 9 through 11 to attach the narrow shelf 2 to 3 inches above the first.
Insert the toe of a shoe into the space between the two shelves. The sole of the shoe will rest on the wider shelf, pushing the toe upward against the narrow shelf and locking the shoe in place.