Ask HN: How to learn best practices when you have no one to teach you?

I am currently working for a startup and am one of 3 developers. Most of my work revolves around building the API in Node + Express as well as some small projects with MongoDB. The other developers don't really assist me since they have their own projects to work on, and, honestly, they have less experience and knowledge than I do.

So my question is: What is the best way for me to go about learning best practices in API development, or using MongoDB, or even just being a better software developer in general?