I use a similar approach as PlasticBattle... but i also like to use surgical tape for "rolled" tarps and canvas. The stuff is about as sticky as a 3MPost-It Note, so that isn't a problem... but it is just sticky enought to hold it's shape while I'm rolling and folding it. It also has a nice rough texture, that is just perfect for "scale cloth".
Like PB, i use diluted white glue/water in a 1:2 ratio of glue to water, often mixing in my base color with the solution. Then when it dries, i come back and drybrush to pick up the cloth texture, using a lighter OD... usually made by mixing 70% OD + 20% Sand Yellow + 10% offwhite. This is applied to areas that are to show more wear. i complete the rollup by adding plastic straps and buckles or knots.