There is a roll of blue-ish clear tape (feels like saran wrap) that you can stick to the ruler. It is non-intrusive and you can definitely feel the difference.
http://www.quiltersreview.com/articl...t/050418_a.asp
Another tip I can give you is DO NOT hold the ruler in the middle. Instead, hold it at the lower third and cut only as far as your hand, then walk your hand up to the next section and cut some more until you have made a complete cut.