It depends what do you want to do(App or middleware in Node.js, frontend of a website, other stuffs(Unity, Phonegap)):
The mayor challenge that I found in Javascript is figure out the best way to organize your project structure. However, there are some libraries that solve that problem.
For web development:
-BackBonejs
-Angularjs
For node.js:
-ExpressJS.
-Bluebird
Also, you should read tutorials about JQuery. This is a javascript library that let you do stuff much easier on javascript.
Finally, I trick that i use to find better solutions or answer are by searching "best practics [topic]". If you feel that you're doing something that's not ok, then you should search the best practices about it.
