Every layout should have a trestle. There is just something about the wooden structures of a trestle that makes for great visual eye candy. This 40 page PDF document (over 30 pictures) shows how I build my trestles and it may be of use to you.
1stclass.mylargescale.com/tj-lee/Trains%20-%20Building%20Scenery%20-%20Trestles%20Rev%2001-01-08.pdf