DIY: How to Build a Shelf

Make a pencil mark on the wall in the location where you want to build your shelf. Place a straight-edge on the mark and align it horizontally with a level. Draw a 36-inch line onto the wall with a pencil, using the straightedge as a guide.

Make a pencil mark 6 inches in from each end of the line. Place a shelf bracket against the wall, 1 inch below the line, and mark the location of the bracket's mounting holes onto the wall with a pencil. If your shelf will be holding heavy objects, it's a good idea to locate two studs behind the wall with a stud finder, then mark the mounting bracket holes onto the wall at that point.

Drill a hole at each of the marked locations. Insert hollow wall anchors into the holes. Place the brackets onto the holes and insert screws into the bracket mounting holes and into the anchors. Tighten the screws with a screwdriver. If you're mounting onto studs, skip the hollow wall anchors and attach the brackets with wood screws, placed through the brackets and screwed into the wall and studs.

Cut a 1-by-12-inch board to 36 inches in length -- you can also purchase this board at a home improvement store. Place it on the brackets and center the board. Drill a small starter hole into the board through the hole on the bottom side of the bracket with a 1/8-inch drill bit. Insert a small wood screw through the hole on the bottom side of the bracket, into the starter hole and screw it into the board to hold it in position.