Sew in Hook and Loop Fastening Tape
Hook-and-loop fasteners, hook-and-pile fasteners, or touch fasteners (colloquially known as Velcro after a company that produces them) consist of two lineal fabric strips which are sewn to the opposing surfaces to be fastened. The first component features tiny hooks; the second features even smaller and "hairier" loops. When the two components are pressed together, the hooks catch in the loops and the two pieces fasten or bind temporarily during the time that they are pressed together.
Made from 100% nylon the Hook-and-loop fasteners come in many different sizes and colours. I used some most recently for fastening Samuel's wallet, of which the tutorial is coming next week.