I find myself rather lacking in web security skills. I have a basic understanding of what TLS/certs/CAs/... are, gotten mainly from Wikipedia and blog articles but I often don't know how to make it all work together. What do you think is the best comprehensive online (free) resource to learn the ropes?
I don't think it is legally available online. Getting the physical book would be the best option since its legal and more thorough than any online resource I've found, but I don't know what your budget is like or if you even like reading books. Just saying that its one option you have.
https://github.com/sbilly/awesome-security