I have been using this method for creating a shank to sew-through buttons forever. I know you all have heard about placing a toothpick under the button, in order to leave some slack for a thread-shank. Well, years ago, I started using worn out sewing machine needles instead of a toothpick. There is a ready supply right there in the sewing room, and I don't have to rummage around in the kitchen looking for a toothpick. I can use the sharp end to secure the SM needle exactly where I want it, and it stays put while I sew the button on. At the last stitch, I pull the SM needle out, wind the thread around the shank three or four times and knot off.
Today I finished another shirt, in the front of which I had managed to errantly serge a hole (and I bet most folks would never guess it had been "fixed"). While I was sewing on the buttons I wondered to myself, "Self, why not share this with the group at alt.sewing?" So here it is. ;-)
I bet all of you have useful little tricks which you have discovered over the years, why not share a few?
Beverly