Lion Brand Yarns, New Stitch A Day and Craftsy all offer online patterns for making crochet buttons. Lion Brand offers five-step directions for making basic buttons. Photographs show each part of the process.
New Stitch A Day offers pattern instructions and a video tutorial for making round buttons. The size of the button depends upon the type of yarn and crochet hook used. Each required technique, such as a slip stitch or single crochet, has a link to instructions for beginners.
Craftsy's pattern is for flat crocheted buttons. Photos illustrate every stage, from making the opening slipknot to creating the shank. The site also includes instructions for embellishing the buttons.