You are a hard-working badass and never forget it.
Trust your mentors
Your mentors think so. Mentors are people that see potential in you that you don’t see for yourself. Trust them. If they are giving you an opportunity to do something, it’s because they have faith in you and know you can succeed in doing it. I cannot stress this enough. And you really need to have the same confidence in yourself. We frequently don’t. Rise to the occasion. That’s the only way you get better.
Do things that are scary
Don't be afraid to say yes to things. Public speaking is scary, new projects are scary, learning is scary. But the only way to get better is to do scary things until they aren't scary anymore (or are less scary).
Collaboration
not
competition
Seriously, there is nothing more boring than people who are still worried about other people. What a waste of time. It will bring you down. Cling to your peers because you are all in this together, now and far into the future.
Learn to code (maybe)
Not a requirement, but all archivists are digital archivists so even basic programming skills will go a long way. Also, developers never have to look for work, even if they aren't that great. I have more work available to me than there are hours in the week (and I'm not that great).
Don't give up
This is an undervalued, underpaid field and there are more people that want to be in it than are in it. The job hunt takes time. You probably won't land your dream job. You might have to take two part-time jobs. You might have to take a job that isn't in the field. You'll probably be a grant-funded employee. Stick with it and you'll get there. But remember Queen Bae's words of wisdom: "You can do everything right and still lose." Just get up and try again.