By working with other people, which I can't help but notice is missing from the parent comment.

Unless you want to be a solopreneur (terrible idea while you don't know what you're doing and don't have the means to hire someone that does), look at pretty much any other comment in this thread.

it's the easiest as it's ever been to get started in a foreign code base: start up the agent and ask questions. more or less instant answers, basically zero confabulations nowadays.

...but since it's so easy to deliver stuff without actually knowing anything, learning means putting in the effort to resist temptation and use the agent as a teaching aid instead of an intern savant.

My advice for juniors is that it's too late to get entry level jobs for software engineering, but AI Automation engineering is just starting. Get a Claude code sub and build whatever you can imagine and focus on improving your own coding agent. Automate one more thing every day.