Add a half-inch all the way around your traced hand to allow for seams, and an inch or more at the bottom of the mitten to create a cuff. Make any other necessary tweaks to your mitten design before finalizing your pattern.
Note: If you have a pair of mittens that fit you especially well, you can use them as your pattern. Just trace around one of the mittens, and add in the allowances for seams and cuffs.
