There are many ways to make half square triangles. You can make one at a time – simply use two squares the same size, place them right sides together and mark a diagonal line on the back of one. Stitch on the line, cut a 1/4″ from one side of the line and press open.
Two at a time is similar but with less waste. Mark a diagonal line from corner to corner and stitch a 1/4″ from each side of the line. Then cut on the line! Here’s a video for that one, I didn’t even mark the line I just used tape on my machine and kept everything lined-up!
More methods to come.
Cheers Sewing Sue