For a deep understanding of JavaScript, consider these tips:

1. Explore Dr. Axel Rauschmayer's books on JS, TypeScript, and Node.js (available at exploringjs.com).
2. If you prefer static typing, use TypeScript for catching subtle bugs.
3. Write Node.js shell scripts to understand JavaScript's low-level workings.
4. Look into JSDoc for an alternative to TypeScript.
5. Try Google's zx library for advanced scripting needs.

These resources and practices will help you grasp JavaScript’s fundamentals, internals, and advanced patterns, elevating your JS skills beyond superficial tutorials.