Modern adaption of the "old school" method:

Way back when in quill pedal days you would ride your bike for a bit without cleats. The rear "edge" of the quill pedal would leave a mark in the bottom of your shoe and then a cobbler (or somebody you trusted) would nail the cleat to the soles with the "slot" lined up with the mark.

When I transitioned to "clipless" this idea wouldn't work, so I came up with a reasonable facsimile. I loosely attached the cleats to the shoes and hopped on a trainer for a ride. When it felt good I stopped and had my wife mark the cleat position with a Sharpie. Twisting out moved the cleats, of course, but now I had marks to do alignments before tightening them up. Worked for me.