I saw this method on someone's blog, and couldn't believe how simple it is. It is a real time saver, so lets see if I can explain. You take two squares of fabric, place them RIGHT sides together. Sew with a 1/4 " seam all the way around. Then you simply make two diagonal cuts with your rotary cutter, and voila!!!!
Now, the size of your original squares, determines what size half square triangles you end up with. For
example, the demo above, I used a 12 1/2" square, so each half square triangle finishes out to 6 inches.
It was so easy, and much faster than other ways I have tried. Good luck!