Ask HN: Joining a new company as a mid-level SWE, what tips would you give me?

Hi, I am 28 with 5 years experience working in finance as a tech person. I am going to join a tech company as a mid-level SWE, what are your suggestions/tips for having a successful career in my new job? What should I look out for? What is the most important thing you can think of?

By successful I meaning climbing up the ladder and becoming a mid-management instead of IC.

Thanks!