1. Slow down. You're building a foundation, focus on learning.
2. Be OK with not knowing. Nobody has it completely figured out, ask questions, embrace the discomfort.
3. Build relationships. You're going to see these people again, I promise.
4. Be kind. When you're kind and helpful to others they will be kind and helpful to you, and you're going to need help from time to time.
5. Take care of yourself. Life is more than work, take time for the things that need time.
6. Don't put Slack on your phone.
What would you say?
I'd just tell my young self to concentrate on the fundamentals and go as deep as possible. Be someone who does NOT need to suck up and "network" and can still find a job even in a recession. Be PURE technical; Don't be afraid to not get a hold on business; Abstract yourself away from business because that's something you are bad at. Maximize what you are good at instead of trying to be an all-round bucket.
Oh and not to get a kid when you are busy advancing your career. Maybe just not get married at all.
Insufficient information to write down? -> see numbers #2 through #6 above.
7b) in fix isn't what happens after using git to update code after a bux fix. see documentaion. See 7a7c) * 90% time on 10% of code may be a thing; but 90% of the project should not be typing/debugging code. see 7a