Here is an idea: Starch your fabric and press without stretching. Then use a template such as Marti Michell to cut squares. If you do not have a 1/4 inch machine foot with an edge on it, then use several layers of blue masking tape on top of your machine to help to make a perfect 1/4 inch seam guide. In class, we used a lined note cards to make sure we had the correct position for the masking tape. This should help you make perfect squares.