Cut all sides of the block of wood on a table saw to get square edges as well as the height and width you want the corbel to be, then sand all edges until smooth. You may have to glue together two or more pieces of wood that are all the same height and width to get the thickness that you want for the corbel. Generally corbels are 2 1/2 times taller than their width; however, they can be made in any height, width or thickness depending on your preference and the look you want to achieve.
Sketch the side profile of the corbel directly onto the wood. The pattern, whether simple or intricately detailed, can then be easily cut out with a band saw. When the shape has been completely cut out, sand all edges until smooth, and remove all sanding dust with a tack cloth.
Lightly apply your stain with a rag, allowing it to dry in between coats, until you get the color you want. When the final coat is thoroughly dry, apply a coat of polyurethane for added protection of your wood and a finished look.
Attach a fitting plate to the back of the corbel with screws. This will enable you to attach the corbel to any surface you choose.