This is something I discovered recently that I'd never known before but would have benefit greatly from knowing it a long time ago. I've realised recently that taking five minutes to learn something new can save you much time and effort in the long run. It's kind of like a real-life implementation of the Don't Repeat Yourself mantra.
For years it's bugged me that starting applications from the terminal kind-of "pins" them to the terminal, so you need to keep this terminal open to keep the application open, but it's tied up with running this one application.
To solve this, it's as simple as adding an ampersand at the end of the command.
chromium-browser &
Edit: A much better way to do this which prevents the application receiving a terminate signal is to append &disown.
chromium-browser &disown