When it comes to coding languages, the best advice (that's tough to follow) is to pick one and stick with it. If you flip between languages or try to learn more than one at a time, you'll quickly find yourself overwhelmed and unable to get past the initial roadblocks.
When you're learning, it's useful to be able to write and run code quickly to see what it does.
JavaScript is a powerful scripting language that runs in browsers. With the creation of Node, people have begun running JavaScript on servers as well as using it to create "native" apps that run outside of browsers. JavaScript has exploded in popularity over the last few years.
Python is a robust language with easy-to-learn syntax. It's used in many environments, from scripting to full-fledged apps and powerful data analysis.
Ruby is a minimal, beautiful language that's used extensively to make command-line tools and scripts. It also powers the extremely popular web application framework Rails. Ruby's simple syntax can be deceiving, as it can be used for complicated scripting and clever metaprogramming.
Regular expressions (often abbreviated as regex) are an advanced way of searching for patterns in text. Learning to use regular expressions can be a great way to improve your workflow and speed up a lot of tasks. Regular expression searching is included in many code editors including Sublime Text and Atom.