Two more useful expressive techniques are the rake and the trill. A rake is achieved by quickly raking the pick across two or three strings leading up to a note, which is then held for it's full value. A rake is indicated by an arrow in the tablature pointing up to the note to be sounded after the rake. A trill is a rapid succession of hammer-on's and pull-off's. It is indicated by a curved line and the symbol tr.
The following lick demonstrates both the rake and the trill.