One thing that used to help me on new lakes was to use something like ExpertGPS (there's a charge for the software, but I thought it was reasonable), which allows you to pull up a satellite map of the lake, easily create waypoints, and then download them into the Garmin. I'd then jot a few of the waypoints on a local hard copy contour map of the lake, so that I generally knew where I was. 'Course, not much help with contours, etc. in terms of exact location, but better than nothing. Honestly, I don't think the contours on most of the chips are worth much (always off a bit) and that a good hard copy contour map combined with the ExpertGPS technique works just as well--just not as convenient.