I did a post about a month ago asking for tips on square in a square construction for my cow quilt. Not doing paper piecing, the most valuable tip that I got was to cut the triangles just slightly larger than the pattern calls for. This worked for me, because when I was finished, I had enough to be able to trim the block to size, and the points came out just right. Another tip was to sew with the square on top of the triangle, because of the triangle's bias edge. Others recommended starching for ease of working with the fabric, but with the fabric I was using, I didn't need to do that. I could see where that might be a help though.
Good luck with your project -- I hope you are as happy with the outcome and I am with my cow quilt!
Dayle