One thing he didn't mention is getting the first and last steps to be the same vertical distance as the others. Nothing will trip you up (literally!) so easily as a final step that is a different height than the other steps.

I thought of this because this morning I was putting a small fence around some plants we want to protect from deer. The fence consisted of 20 sections (bought on Amazon), each about 24 inches wide. Our ground is like rock, and the fence was not that sturdy, so I had to pound a heavy spike into the ground to the depth of the fence posts, then pull the spike out and put each section's legs in, leaving room for the next section's leg to go into the same spike hole. I wanted to be sure I was putting each section in at the right position, lest I end up with a 12 inch gap and have to go back and adjust lots of sections. Long story short, I pretty much succeeded, although when it cools down I may adjust a few sections. But the problem was sort of like the stairs: I wanted an integer number of fence sections, each the same length, to exactly fit around the bushes---just like you want an integer number of vertical steps in a diagonal stair, each of the same (more or less standard) height.