Books, websites, videos, seminars, and all that are fine, but when it comes down to the best way to learn the things that will be of value in your career, it’s from a real, live person you can talk to and ask questions.
Not everyone will have something to teach you. And many who say they do will be full of crap or, just as likely, trying to sell you something. It’s up to you to be on the lookout for those who do.
They don’t have to be bosses or “mentors” or “coaches” either. You will find in life that many of your most valuable lessons come from people who aren’t trying to teach you anything — they’re just doing their own thing and you’re lucky enough to be around them when they do.
Soak it up. Ask questions, but not too many. And when you’ve figured it out, put it to work for you.
Lather, rinse, repeat.
And later on in your career, when you’ve got knowledge a newbie could use, share it with them. It’s only fair. (You’ll probably learn something too.)