I'd recommend a bit of freelance or studio work before setting up your own - make mistakes and learn on other people's money rather than your own! When I started Hellicar&Lewis with Pete, it was just a day a week that we agreed to spend together working on ideas and experiments. The rest of our time was spent freelancing for ourselves - so we still had money coming in to keep us alive. A great book on how to talk about yourself and how to work in a sustainable way is:
Win without Pitching. Message me on Slack if you are interested in learning more. The biggest tip I can give you around running a studio is try to keep your costs down - UniversalEverything has done that by being a remote studio from 2004 - which means we can say no to projects if we don't like them, rather than getting trapped in a loop of doing work for projects we don't like, which is never as good as working on things you love. If you want a recent survey of how lots of design studios are operating around the world, I can't recommend
Studio Culture Now from Unit Editions enough - it's a great survey of some of the most interesting studios in the world, and how they do things. Finally, be nice! Your reputation will travel further than you can.