I mark a diagonal line on one square, place it over another square and stitch 1/4" on each side of the line. The I cut on the drawn line to get two half square triangles. At that point it doesn't matter if the ruler nudges over a bit as your seams are already sewn. I don't care to work with sewing triangles together and I don't care to work with bias pieces. The nice thing is that each of us just needs to find the way that works best for us and do the piecing that way.