Learn a handful of knots. You don't need to know the entire boy scout manual, but solid understanding of 4-5 knots - be it a trucker's hitch (adjustable), improved clinch (fishing/permanent), half hitch, etc - will be the right tool for the moment. When we go camping, we end up bringing a handful of tarps and paracord. Always fun to see the monstrosities people come up with as we try to string up a sun/rain shelter.