Very basic question. I have a rotary cutter but never seem to get straight cuts. My ruler always seems to slip. Is it because I'm applying too much pressure trying to cut too many layers at one time? As a general rule, how many layers do you cut at a time and what can I do to get my strips or squares as nice and straight as I've seem on here? Thanks.

There is some really good information here:
http://quilting.about.com/od/rotaryc...ing_strips.htm

I never cut more than 4. good luck

I don't cut thru more than 4 layers. Some people put little sandpaper dots on the wrong side of the ruler that goes against the fabric. I just try to keep an even pressure and put my little finger of my left hand (I'm right handed) on the table braced up against the edge of the ruler to keep it from slipping. When I start having issues, it usually means I need to change my rotary cutter blade. I'm bad to forget to change them.

I don't know what kind of ruler(s) you have, but I like the Omnigrip, cause all the grid lines are a sort of thin rubber, which tends to, well, grip the fabric. If your ruler is slipping consider adding some tiny sandpaper or rubber grips. Also, make sure you aren't pushing sideways too hard against the ruler. If I have a nice new sharp blade I might cut six layers, but if the fabric is heavier, then four. Depending on the fabric, each layer adds a certain amount of slipperiness! My rule is: better to cut only a few layers and do it right, rather than rushing to cut a ton at a time, and then having to go back and fix errors. Those tiny 1/16 inch bobbles from a ruler slipping add up!