Thanks for all of the tips, everyone! I've been thinking about trying something a little easier, but I'm determined to make this work. I'm anticipating lots of setbacks, but I've always been someone who enjoys overcoming challenges and I think that keeps me from feeling discouraged when I can't do something right away.
I cut out about 60 paper triangles and I'm practicing with them so I won't ruin any fabric. I've been laying the triangles on my ruler, placing the next one 1/4" below the point, and taping the opposite side in place (I'll use pins when I try this on fabric); it's much easier for me to do it this way than to make adjustments and keep re-measuring. The only problem I'm having now is that the paper isn't very flexible, so it's kind of hard to sew in some areas!
But so far, so good! I'll find some old clothing to cut up and practice with this weekend before I dive in!