I have a pretty intricate folder system on Dropbox under "Business School Stuff" where I saved down all the information I could find on the schools I was interested in (e.g., brochures, employment reports, Clear Admit guides). For each school, I had a notes document (e.g., "Booth Notes") wherein I kept all the notes I had gathered on each school's offerings, including clubs, programs, professors, and courses. As I started reaching out to current students and visiting schools, I kept an Excel document titled "Business School Contacts" where I logged everyone's names/background, which really helped me personalize my essays.
I also had a pretty thorough bookmark system, too, where I would save any relevant article or club page. If you haven't started browsing Poets and Quants (
https://www.poetsandquants.com), you should. I also read a few books on the process, too. Check this thread for recommendations:
https://gmatclub.com/forum/best-books-on-b-school-applications-146441.html.
I hope that helps or you at least got a chuckle out of how obsessed/anal I was!

Edit: I forgot to mention two other spreadsheets I found very helpful. I kept an "Application Deadlines" spreadsheet with submission deadlines, notification dates, and deposit deadlines. This really helped me stagger my applications so I wasn't submitting 5 within the same one-week period. I also kept an "Essay Questions" spreadsheet, where I put the essay questions and the themes of my answers. This way, I had an "at a glance" view of all the "stories" I had used and where they could be used again (if possible).