Step one, drag all the even vaguely suitable yarns out of the closet.

Step two, which is alas shamefully unpictured, is swatch a bunch of little plain rectangles to see what gauge we’re working with, so you can imagine a bunch of little rectangles here if you want.

Step three is to pick one, do a bit of math and cast on.

Then alas, in this case, step four was to realize it wasn’t the best fit and rip.  Under ideal conditions, this step should be skipped.

Step five is try again, and this time…this time I think we’ve got it!