Artangel: Mixed media crumpled tissue technique - tutorial - basically, glue tissue paper over a canvas, let dry. Paint, let dry, then rub pastel or chalk over the surface to highlight the texture. Would be an awesome way to vignette around a painting.
Ripped pages can give hins of what is yet o come an encourage your viewer to keep turning th pages of your interesting sketchbook. To be used appropriately rather than throughtout the entire sketchbook.