Definitely take the below with a grain of salt - this worked for me thus far but there are probably paths other people have taken that worked equally well or better :) My recommendation would be: 1) A smaller/less established team where you'll be responsible for building out key chunks of the team 2) A team where you can build expertise in a domain you find interesting, and where you think there might be more problems than solutions

The benefit of working on a smaller/less established team is getting the autonomy to build something that's immediately impactful to the company and its customers, while not having to worry too about how to stay alive (fundraising, revenue, resources) - I think that's pretty good training for building a startup.

Picking a team where you'll get expertise in a newer/growing field can be helpful too - think something where you'll only need a few years to become an expert and start adding value. Also be sure to pick something you like, since if you do start a company in that field, you'll likely be spending a big chunk of your life on it.