There's a lot of things I have to say about gluten-free baking, but here's my main approach: use a tried-and-true flour-containing recipe, and replace the flour with a mix of gluten-free flours and xanthan gum. It works for me every time. Different baked goods require different combinations of starches and starchy flours and hearty flours. For cakes, I like the ratio of 2:1 starchy flours (rice, millet, corn) to starches (cornstarch, potato starch).
I'll post a full recipe soon, but basically I just replaced the 3 cups of flour the cake recipe called for with my 2:1 ratio. I used 1/2 cup each of: white rice flour, sweet rice flour, brown rice flour, millet flour, cornstarch, and potato starch, plus 1/2 teaspoon xanthan gum. I hate the taste of tapioca starch, so I never use it. I think that it's what makes things have that funky "gluten-free" taste.
So don't throw out all your beloved family recipes that use wheat flour; just make a simple substitution! The resulting cake was slightly denser than your average layer cake, but it was moist and had a good crumb. Full recipe to come!