Here is where you select what it is colliding with, how far away from the mesh you want it, and you can also have it ignore body parts that it won't be near so it doesn't have to waste time calculating.

Also, if your final pose is one that may cause unwanted bunching, like sitting...
You may want to drop the friction values here a little to allow it to slide instead bunch up.
Chances are, for now you won't need to.