Generally, I will mark with a pencil where I need to cut my fabric for a home décor project. However, if I have to work with linen or another fabric with an obvious cross grain, I pull a thread. This ensures that the top and bottom of your fabric are perfectly parallel. You may have to block the fabric after you cut if it is obviously dipping or sagging in places. I also use this method if the fabric is more fluid and doesn’t like to maintain a straight line on its own. If you use this method to cut a PRINTED fabric, you will notice pretty quickly if the fabric was printed ‘straight’ on the fabric.