Always carry extra batteries for the GPS--and always carry a conventional compass on top of that as a backup!
If I'm hunting some place new, I always will have studied an aerial map first and know where landmarks/civilization are along the traditional NSEW compass points.
I never rely on only electronics when it comes to life and (possibly) death situations. Someday that cheap manual compass just might save my life when my very expensive GPS unit decides to flake out.
I also learned the value of using a lantern this year to track after dark. Not saying you should lug it around in the woods with you...but have it in your truck or some place close.