I bake entirely from scratch too. I know there are many cake decorators who use a mix (or a doctored mix) but I can always tell a mix cake, even a doctored one. Years ago I used mixes, but then I started to feel like I was cheating when people started paying me for the cakes. Also, I felt like scratch baking is a kind of dying art form and I was determined to learn it. Now I will not go back.
It can take many tries to find recipes you are happy with. I had the same problem with dryness, but I kept trying new recipes and found ones I love. I also got an oven thermometer and I check the temp every time I bake. I am careful when I measure my flour (I spoon it into the cup measure then level it, instead of the ol' "dip 'n' sweep method, or I measure it by volume). Lastly, I am careful to watch the time when baking.
If you need some good recipes, I have a scratch-baking blog you can check out: www.bakeoutsidethebox.blogspot.com