Place a roller pad with 1-inch or thicker nap (padding) on a roller frame. An old pad that has been used and not thoroughly cleaned (so some of the tufts clump together) works best for this.
Stretch and twist rubber bands around the pad at a variety of angles, creating clumps and random patterns with tufts and lines.
Apply paint to your walls with this roller as you would with any roller, but slightly adjust the rubber bands periodically as you work to renew the texture.
Fluff up the nap with a comb if it becomes too flattened to give you a good texture.
Dampen and squeeze out one or two rags, about the size of standard hand towels. Terrycloth rags are great for rough textures, while T-shirt-type rags work well for softer textures.
Wrap the rags loosely around a standard roller pad on a frame.
Secure the rags with rubber bands at random angles and positions so the bands add to the texture.
Pull the rag out from the rubber bands in some places so it has puffy spots and even a few loose ends that will flop around as you paint, adding to the texture.
Apply the paint as you would with any roller. Puff up the rag or tuck it under the rubber bands as necessary to keep the texture fresh as you paint.