Regardless of your recipe, here are some tips that have HUGELY changed my biscuits:
Use cold butter right out of the fridge and dice it up to mix it into your flour. The coldness helps to keep the biscuits fluffy. In general, use more butter than the recipe calls for. I use 1/3 more.
Mix your dough as little as possible. It is not bread dough; it needs to remain airy - not become dense.
Keep your dough too wet to handle without a layer of flour in between. Pour it out on a floured surface, and then sprinkle more flour on top. Dip your biscuit cutter in flour before cutting each biscuit so that it doesn't stick to the wet dough.
When you cut the biscuit, DO NOT TWIST the cutter. Press straight down and lift straight up again. The "twist" lets the air out of the dough and will keep the biscuit from rising straight up.
When you place them on the pan, put them close together so that they "encourage" each other to rise straight up.
I read most of these tips on somebody's blog and I wish I knew which one it was, because I'd love to go back there and thank her for sharing these tips with me! I am truly sorry that I cannot give her credit here.

If I find that blog again, I will update this post.
love,
Beka