Do a Resection With a Map and Compass
Orienteering -- the skill of finding your location and navigating using just a map and compass -- is a rapidly dying art in our modern world of global positioning systems, mapping websites and hiking trails paved with asphalt for the benefit of people in wheelchairs.
Keep and study nautical charts of all the waters you sail, even if you are familiar with the waters. If you know how to read a nautical chart you will know which direction to go, depth of water and location of harbors.