Strong Elastic (about 1/2" in width)
Optional: Trim/material to border wrist
To get started, you need to determine the size of hand you are making a bath mitt for. If you happen to have the kid you're making it for hanging around, use their hand as your guide. Make sure they'll have enough room for their hand in the mitt without it being too tight, plus an extra 1/4" - 1/2" border for you to sew around. Make sure the wrist section at the bottom is wide enough to get their hand through (don't worry if it too loose, you're going to add an elastic to it), and long enough so that it sits below the wrist.