Originally Posted by Sadiemae
What size ruler are you trying to use? I find that I use my square rulers a lot when cutting smaller pieces. Invisigrip is good and I also use the tiny little sandpaper dots that are self adhesive from Lowe's or Home Depot. I also have the Gypsy handles that go on the rulers and I really like those. They give a lot of control.
The small sandpaper circles (about 1/4 inch across) help minimize slipping a lot.