You probably have up to 20 fabrics. Sew strip 1 to strip 2. Sew strip 3 to strip 4 etc until you have all your strips in pairs.
Then sew 1&2 to 3&4 and 5&6 to 7&8 etc. until you have all your pair in groups of four. Continue until you have the strip sets done. Now you are ready to sub cut into strips of different widths.