2) Don't write theory, write applied principles. I wouldn't share anything that was put together by one of your professors - that is their work. But if you apply their lessons to something in your own work/life, you absolutely can tell us about it, and outline the academic principles involved as you go.
> “The pen is an instrument of discovery rather than just a recording implement.” —Billy Collins
As for #2, if you have a friendly prof for a relevant course or two, ask them directly! Chances are, they'll be happy to have you write about what you learned from their class, and may even be willing to read your posts and give you feedback.