I found that out the hard way! I love all the tips and advice given here.

This is my preferred method, too.

I've also found that when the square is "N"+7/8th inches, the quarter square triangles are more uniform in size than if the square is an even number.

Missouri Quilts has a YouTube video showing how to make 1/2 sq. triangles. Jenny sews around 2 sqs. She then cuts on the diagonal to make 4 1/2 square triangles. Hope this helps.

Mamahen you are right! I did learn this the hard way. I had not used this method before since I had heard that it was not always true HST but since I had to make so many of them I diid try it. I also marked each diaginal be for cutting square apart to make it easier to be sure I cut on the diaginal. If I am only making a few HST then I will probably make the the old fashion way

If you have problems with half square triangles, invest in the CD called Triangulations. It's about $30 and well worth the investment. You can make hst and flying geese any size you want. You need a printer but you can just print out the size you want, sew and cut on the lines and they come out perfect every time.