You can choose to use brackets specifically designed for floating shelves, making them invisible to the eye. You can also build your own hollow shelf and then slide it right on to a wooden cleat. Lastly, there's the option of using figure-eight fasteners to hold your shelf up on the wall.

To hang the shelf, first mark its location. It’s best to screw the cleat into a wall stud, which you can locate with a stud finder. If that’s not an option, use drywall anchors to add strength. Position the cleat on the wall. Use a small level to adjust the placement. Screw through the cleat and into the wall with 2 1/2-inch screws.