Disclaimer: since I'm a programmer, by technology, I mean technology revolves around that. It may applies to others too though.
How do you learn new tech? With all new stuff pops up every minute, at some point you'll have to learn new stuff in order to stay relevant. Let's face it, stop learning new stuff for couple years, you'll having problem finding works. And I don't even talk about Humans Need Not Apply-kind of irrelevant (which is great video by the way, you should watch it if you haven't. go. watch it. now).
Learning new stuff is easy with internet. The resources are there. And you don't even need much time. 20 hours is all you need is all know enough. Yes, some said to be good at something, you need to spend 10,000 hours on it. But in the spirit of learning new stuff, those 20 hours are enough to get you started building something. Well, of course you shouldn't abandon it after 20 hours. You should reach the 10k hours if possible.
And I haven't answer the question. So here's how I learn new stuff. I read, try, read, try, read, try, and ask. And read a lot. Most of the time, for whatever you're learning, there's already best practices, RFCs, READMEs you can (and should) follow. Sometimes it looks harder, but unless you have a very good reason to do it your way, don't. It's easier for others too, if you happens to work with other people.— 20140925 – aldi —