Giving a room cottage style is as easy as putting brush to wall. To create faux planking, space stripes 6 to 10 inches apart, using the room's scale as your guide; for a wainscot-like effect, add vertical lines below an existing (or new) chair rail. Your most important tools for getting them all just right: some good painter's tape; a plastic putty knife for smoothing tape in place to prevent seepage at the edges; a 4-foot level, to be sure lines are straight; and patience. Diligent prep leads to top-notch results.
See a detailed how-to on this type of painting project.