When it's all done, the picture is a mess and students are stressing that they'll have to replicate all 15 (or however many) steps there were for every problem. "Wouldn't it be great if we had some shortcuts to follow?" I asked. "Do you notice any commonalities that we could look for again in the future?" Some angle pairs jump right out, but even the others aren't hard to see with a little effort.
So I created 4 copies of the framework of the picture (just the parallel lines and the transversal) and identify one pair at a time, naming them as I go along.
Students then had ~20 minutes to work on U6 WS1 and were told that it would be checked (for a grade now) on Monday.