Fold your towels the way you normally do and measure their length and width with a ruler or tape measure. Determine how many towels you want to lay side-by-side on your shelf to determine how long your shelf needs to be.
Purchase a precut board made of the wood of your choice or cut your own with the type of saw you prefer. Examples of types of saws include circular saws, jig saws, table saws and handsaws. If the width of your folded towels is 12 inches, purchase a 12-inch-wide board. Cut the board as long as the measurement of the number of folded towels you want to lay side-by-side. For example, if you want to lay two 10-inch folded towels next to each other, the board should be 20 inches long.
Measure the spot where you want to mount the shelf. Mark the spot with a pencil. Measure horizontally from the marked spot and make another mark at the position 2 inches away from the length of your shelf. For example, if your shelf is 12 inches long, measure 10 inches horizontally from the first mark. This will allow you a 1-inch overhang on either side.
Hold the shelf brackets, one at a time, so the top of the bracket is even with the top line. Mark through the holes in the brackets with the pencil to guide your placement of the screws.
Drill holes through each of the bracket marks you made in Step 4. Use a drill bit slightly smaller than your drywall anchors.
Push the drywall anchors into the holes, tapping them lightly with a hammer, if necessary. If you drilled into a stud in the wall, you will not need anchors.
Change the bit in your drill to a screwdriver bit. Hold the bracket so the holes line up with the anchors. Drill the screws through the holes and into the anchors or wall studs.
Lay the board on top of the brackets to complete your shelf.