Measure the space where the bookcase will go
Decide the bookcase height, width, and depth
Choose your materials, such as plywood or solid wood
Gather tools, including saw, drill, screws, tape measure, level, and sandpaper
Cut the side panels, top, bottom, shelves, and back panel to size
Sand all cut edges and surfaces
Mark shelf positions on the side panels
Drill pilot holes for shelf supports or fixed shelves
Assemble the frame by attaching the top, bottom, and sides
Install the shelves at the marked positions
Attach the back panel to square the bookcase
Check that the bookcase is level and square
Fill screw holes with wood filler if needed
Sand again after filler dries
Apply paint, stain, or finish
Let the finish dry completely
Secure the bookcase to the wall if needed