The following tools will help you as a developer regardless of what branch or language you specialize in.
Two main benefits to improving your command line skills: you can focus on the actual command rather than the syntax of it (npm, git, etc) and improved speed when performing common operations (that could also be done with the GUI... but slower).
Learning the Shell on linuxcommand.org
Command Line on linuxjourney.com
How to read man pages on cs.mcgill.ca
Version control is necessary, in order to keep track of all changes and older versions of source code files, and to facilitate collaboration.
Consistency in the codebase is key, especially when working with other developers. We can use linters -extensions for a code editor that analyze the code to point at potential errors- combined with style guides to ensure respect of good practices, and a consistent style accross a project.
eslint
google JS style guide
airbnb JS style guide
Setting up ESLint on VS Code with Airbnb JavaScript Style Guide on travishorn.com
Debugging with print statements will only work to a certain extent, and while it may still remain one of your go-to when hunting for the source of dysfunctioning code, there are other options that will come in handy, especially when working with more complex projects, e.g when the steps to trigger a bug are tedious to reproduce.
Node.js debugging in VS Code with Nodemon
React app debugging in VS Code with Debugger for Chrome