Be sure to cut with your rotary cutter straight up and down, not leaning in at an angle and pushing on the ruler. If I can, I keep my little finger off the edge of the ruler to give it some stability. And moving your hand along the ruler is good advise. If you think of it like this- if you don't move your hand, it ends up becoming a pivot point, just like if you were using a compass. If you move it along, your hand stays next to the cutting and there is a smaller chance your ruler will move. Also, when you do that, leave the blade IN the fabric, slowly move your hand, being careful not to jostle the ruler and put it down carefully, again so y don't jostle the ruler. I also like invisigrip.

My favorite way to keep the ruler from slipping is to use an 8 pound hand weight (like you would use for exercising). I place it on top of my ruler and it does a great job in preventing the ruler from moving. I have 2 of them and use both on my longer rulers.

I too use the spider method of walking my hand down the ruler...it definitely keeps the ruler from moving and if I'm using a narrower ruler (my 6 inch wide one or one of the smaller ones) I can put my pinky off the far edge and give it even more stability.

I'm one who uses rubber cement - it solved all my ruler problems. It's nice because the ruler holds snug all along rather than just in a few little spots. It's easily removed/redone if it gets too linty. It does take time to dry, especially when the humidity is high.

As you walk your hand down the ruler, as others have mentioned, be careful never to let your hand get ahead of the blade. The blade jumped the ruler one time and I learned my lesson about that! It was just a little cut, but could have been much worse.

DITTO about Quilters Slidelock..... I have both sizes and worth the money ,I only wish they had come along sooner.

Use the classic method. Lay your opposing pinky along the edge of the ruler on the opposite side from where you are cutting. Press straight down with your rotary cutter instead of pressing against the edge.

I bought Grip Strips to help with this issue and I found they made the ruler up too high and I would get an incorrect cut. btw I also bought their gadget to make two rulers stick together to make a right angle cut -- they had the suction cups upside down. I kept wondering what I did wrong, lol!

When I made a pinwheel tree skirt I followed the advice to put packing tape on the back of the ruler, that worked! Apparently the edges of it were sticky enough to keep the ruler in place. Good thing since it was a homemade ruler.

When I cut I put one finger off the ruler to the left-I am right handed. This one thing has really saved me the slips.

None of my Creative Grid rulers slip, so I'm slowly moving to that line. Also, if I'm cutting large numbers of strips, I SWEAR by the June Taylor Shape Cut Plus rulers. I found out about them on this board and I swear I don't know how I lived without them. I can cut 6 strips accurately with no slippage in about 30 seconds or less!

Wow, seems like a lot of work just to cut a strip(s) of fabric, but on the other hand great exercise for arm, back muscles!

I have used those clear "buttons" that you put on the bottom of things to protect the surface, on the ruler too. You can also find them at the dollar store. Then I found this clear sheet (at Joann's) to put on the back of the ruler, it just clings on. It works well, but recently it starts to peel at a corner of one of the rulers, I think it's from me trying to shove it in the crowded place.