I'm with the native texan. I trim two sides once I've got my ruler in the right place. Then I'm sure I'm not trimming one side two times. I start a 1/2" larger too, just to make sure. Are you making two HST per starting squares or trying 4. I can't do 4. It never works for me.

Trim it to fit.

I think you are right, I cut them 1 inch bigger and square them up, with the small square ruler with diagonal line on the seam to get the points right.

Make them 2 7/8 then draw a line corner to corner and sew 1/4 inch on each side of line then cut on centeer line. Hope this helps.

wow, that tute is GREAT!!! Thanks, Jan, for sharing it.

Do you press open the square? Sometimes that misalines the fabric. Find a tutorial, follow it religiously. I just started using half triangles and now it's my favorite things to make.