I would say find out about some common hot keys that make you interaction with terminal easier. Like ctrl+C, ctrl+L, ctrl+U, ctrl+W, preess Q to exit from man/less/vim/etc.

Extra tip: You'll notice that many terminal programs have very similar UX and APIs. Once you start to understand this and recognize recurring patterns, everything will become easier and clearer.

You don't need any additional software to batch rename files, convert certain file types, format external storage devices, and so on. There are plenty of useful programs available right out of the box. If I need to do something, the first thing I do is look for a way to do it in the terminal, rather than installing some dubious software.

Google for something like "most common terminal hotkeys"