Measure the top of your ottoman. Create a pattern from your measurements on a sheet of tracing paper. Add approximately 1/2 inch to each side of your pattern and cut out.
Position your pattern over a piece of upholstery foam and trace out your shape. Using a manual or electric utility knife, cut out your foam cushion. Spray a layer of spray adhesive to the ottoman frame and place your foam over the top. Allow the adhesive to dry.
Wrap a layer of cotton batting over the surface of the ottoman. Pull taut to the underside of the frame and staple the batting in place. Cut off any excess. To keep the batting from shifting during use, use spray adhesive to coat the top of the foam before attaching the batting.
Cut your upholstery fabric and place over the top of your ottoman. Pull it as taut as possible and staple it to the base of the ottoman beneath the cushion. Leave approximately 1/2 inch of excess fabric around the staples to account for pull as the ottoman is used.
Create a skirt for your ottoman by wrapping fabric around the sides of your ottoman. Cut your skirt to your desired size, adding 1 extra inch of material on all sides to create a hem.
Fold your fabric under 1/2 inch on all sides and press with an iron. Position a strip of fusible tape over the folded width. Fold over again 1/2 inch to cover your fusible tape. Press your iron over the hem to melt the fusible tape and secure your hem.
Staple your fabric skirt in place at the top of the ottoman below the cushion. Hot glue decorative ribbon or piping over your staple line for a more finished, professional look.