I get them to fold up to about a 4" x 5" square. I fold them lengthwise until they are about 4" - 5" wide, then lay it on the floor (or deck), and then either roll or fold it from the bottom (closed end) towards the open end, thus forcing all of the air out the open end of the bag.

To sleep in 1 of these bags, being 5'8" in height, I wrap up in a blanket (or two), snuggle down in the fetal position, and have a good night's sleep.