How to cut straight across a piece of fabric

If it’s important for your project that the fabric be cut exactly on the cross grain, try using one of these methods:

For loosely woven fabrics, pull a thread (use a pin to lift the thread) and remove it all the way across; cut along the void left by the pulled thread.

For tightly woven fabrics, snip the selvage and tear. Don’t force the fabric, if it doesn’t tear easily, spread it out and draw a line perpendicular to the selvage using an L-square as a guide.