To maximize learning, my main advice is:
- Don't go to a big company research center. Go small - the smaller the better.
- Don't stay in one place too long. Startups in particular are good for this - spending 6-18 months at a company is considered normal in that space.
Out of college, I spent five years bouncing around startups of various sizes as a data scientist. My girlfriend spent her first five years out of college at Google. In terms of learning, there was no comparison: I experienced multiple industries, multiple tech stacks, worked with multiple teams, and within each job I wore multiple hats and did a variety of different kinds of work.
At a job, you're going to learn the most within your first few months with a team or your first few months filling a particular role. After that, things slow down a lot. So, to maximize learning, shorter stints with smaller teams are best, since they force the most variety.