Own only what you need.
Over time we fill our houses, basements, and lives with useless crap. Stuff that either we needed once, but don't anymore or that it's completely superfluous. Stuff we don't need. I come victim of it, just as much as everyone else.
I tend to buy only what I need and nothing else. It allowed me to save enough to leave my full-time job (at the beginning of the year) and try working on my own as a freelancer while having a safety net of 6 months of living expenses ready if the freelancing gig would fall through. Fortunately, that didn't happen, but if it did I wouldn't be forced to find a new job right away. It also saved out of a lot of stress.
But being minimal is not queal never buying anything. It's owning and having only what you need.
Digital nomadism is the idea in its most ultimate and radical form (read Krause article about only owning a suitcase and traveling around the world as a digital nomad and similar stories from Daniel).
You don't need to be a digital nomad to own only what you need though. If you have a house you are going to obviously own more than someone who doesn't, but that's not the point. The point is not to own as little as possible, and it's not even to fit all of your belongings in a single suitcase. The point is to own enough. What you need and what you want to own without excesses and useless clutter.