I also make half-square triangles 1 inch larger and trim to size.
e.g. If I want 3" finished half-square triangles I cut a square of fabric 8" X 8" from two fabrics. On the lighter fabric I draw the diagonals from corner to corner and across midway on the sides. Sew 1/4" seam on both sides of the diagonals; cut on the diagonals and across. This gives you 8 slightly larger half-square triangle blocks. Trim each to 3 1/2" square.