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.
Not watercolor. Want to learn how to paint trees? This very detailed step-by-step tutorial will show you how to paint 5 different trees. You will amaze yourself and enjoy these techniques every time you use them.