Measure the wall space and decide the shelf size
Choose the shelf material
Gather tools and hardware
Mark the shelf height on the wall
Locate wall studs or use proper anchors
Cut the shelf boards to size
Sand the edges and surfaces
Apply paint, stain, or sealant if desired
Install shelf brackets or supports
Attach the shelf board to the brackets or supports
Check that the shelf is level
Tighten all screws and fasteners
Test the shelf with light weight first
Add items gradually and evenly