This is my favorite gluten-free flour mix. I use to make cookies, muffins, pie crusts, tea breads, and other baked items that don't require a lot of elasticity like breads.
Make up a double or triple batch, be sure to mix it all well, and store the lot in your freezer so you can make a batch of you-name-it, when every you please.
2 1/2 C white rice flour (or you can substitute brown rice flour here for a more healthy and hearty muffin or tea bread)
2/3 C sweet rice flour (there is a big difference here between regular and sweet rice flour. I get my sweet rice flour from the Asian grocery)
1/4 C potato starch
1/3 C + 1/4 C tapioca starch
And that's it.