How do I become a better developer?

A few days ago I asked a question about moving from Meteor to a new framework and got a couple responses that changed my perspective to focus on just becoming a better developer. I also want to apologize for the negative tone of that post.

One of the responses mentioned this:

"Look at the core fundamentals of JS, HTML and CSS. Develop a solid understanding of programming principles in general: proper code and project structures, creating simple readable code for reuse, etc."

I have used the following:

• Google search
• Lynda.com
• egghead.io
• Stack Overflow
• Javascript: The Good Parts by Douglas Crockford
• Mozilla Developer Network
• local Meetups

So what are some resources you use to become a better developer?