Gather materials: wood strips or cardboard, ruler, pencil, saw or craft knife, glue, clamps or tape, sandpaper, backing board, glass or acrylic, hanging hardware
Measure the picture
Decide the frame size and cut the frame pieces to fit
Cut 45-degree mitered corners or straight butt joints
Sand the cut edges
Dry-fit the pieces
Glue the frame corners together
Clamp or tape the frame until dry
Cut and fit a backing board
Cut and fit glass or acrylic if needed
Paint, stain, or decorate the frame
Insert the picture into the frame
Add the backing and secure it
Attach hanging hardware or a stand
Check that everything is aligned and secure