Fishing Knots. This is the one skill that just may save your life one day. Don't put it off. Learn them and do them every day(while you can) for several months, so it's in your muscle memory and you don't forget them. You can't trust that someone else is going to help you or save you ; when you need them to.
Here is a very interesting set of various climbing knots from "Animated Knots by Grog" that apply to paracord. These animated knots are for climbers, rescue workers, arborists, tower-climbers, and others who use rope in man-carrying applications. http://www.animatedknots.com/indexclimbing.php
[Animated] Knots! "Better to know a knot and not need it, than need a knot and not know it" :) Hover over the knots at this link to see their uses. Click on the knot to see an animation of how to do it.