I was officially diagnosed 2 or 3 years ago, although my parents were told when I was 7 that there was a possibility of me being bipolar. My advice either comes from my personal experience (medicated, leans towards depressive) or from what I have learned from my aunt (unmedicated, definitely more manic).

1. Always be open and honest about what's happening with you. That way if something is wrong it can be addressed and hopefully fixed.
2. If you're on meds, always remember to take them. Don't skip them, don't drink when taking them.
3. Try to find a way to track your mood that works for you. Keep a journal, download an app, use a chart. This can be extremely helpful and over time when studied can help to identify triggers.
4. Stay involved at appointments. Do some research on meds and come up with questions. It's always good to know about what you're taking.

There's probably a billion more things I could say, but I can't think of them at this very moment. For me these are the main things that help.