Making Shelves With L Brackets. The project is extremely simple and you can find its full description here. The shelves themselves can be simple wooden boards.
They are simple to use and are usually good for a variety of shelves. Several shelves, staggered on a wall, make a serious design statement. It requires three pieces of wood.
Further, for really heavy and wider shelves (closer to 12″ wide), i would only use these brackets if you can secure them to the wall studs instead of drywall.
Just make sure the seam is on a bracket. Step by step building instructions & how to hang floating shelves without brackets. We made these brackets based on planning to hang a 1″x8″ shelf. We used 1×3 lumber for these brackets, meaning they are 3/4″ thick by 2 1/2″ wide.