Rebecca showed us her 10-minute tip at the meeting this week--a super quick way to make quarter-square triangles. Quarter square triangles look identical to half-square triangles, but the grain runs along the long diagonal edge instead of along the short outer edges. The quilt police would probably be horrified, but you can use half- and quarter- square triangles interchangeably if you don't care and are very careful to avoid stretching.
Her tip was based on this blog post from That girl... that quilt, method #1. Rebecca's spin on it is that instead of doing a bunch of math, just add 2 inches to the unfinished size of your block. So if you are trying to make a 3.5" unfinished half square triangle, cut out 5.5" squares. You might need to trim your blocks a little after sewing, depending on the size of your seams.
We also talked about how you then need to be very careful pressing (no steam!) and piecing as the outer edges of the square will be stretchy. Flaun suggested starching the pieces in advance as well, as that would reduce the stretching.
Leslie also commented that if you cut your squares on the bias in the first place, which would be easy if you were using scraps, then the finished half square triangles would have the grain running along the outside edges.