There are several gluten-free flour mixtures, including commercially prepared ones. If you’d like to make your own, Living Gluten-Free For Dummies suggests you combine two parts (equal amounts) rice flour with 2/3 part potato starch flour and 1/3 part tapioca flour. For example, if you wanted to make 6 cups of flour mixture, you’d use 4 cups of rice flour, 1 1/3 cups potato starch and 2/3 cup tapioca flour.