I believe knot-tying would be a great, life-long skill to have, especially being able to know which knots work best for different situations, like when the rope is thick and not very flexible or bendable.
I have lots of nylon rope and fishing line of various diameters, but don’t know where to begin and/or the best way to get started. My goal is to make this a long-term hobby and spend 1-2 hours per week improving my knot-tying knowledge, skill, and speed.
Being able to hang your own hammock will feel fairly badass. I think the best answer is to take the route that you know will actually get you to practice. If that’s a book for you, great! But if you know that you’re likely to lose interest with a self-driven method then an outdoors club could be just the ticket. Depends on what kind of person you are. Maybe the Sierra Club?