Some of my mistakes are;
The D-Rings were smaller than I thought, though I can get my fingers in them to extend the strop.
My staining of the raw leather strop & the leather clasps that hold the hardware on the strops is poor,,,, I forgot to wear gloves,,, I have vintage brown fingers now,,,
The shiny brass screws don't match.
I can't cut a straight line,,, wasted a lot of leather.