Matt,
A perennial question, but one always worth asking.
I've got a few recent(ish) posts that'll help. Some of them are more BIM focused, so as a Revit user you probably understand that stuff already. But starting a new program it's worth reviewing the basics of why we do BIM in the first place as it'll help you stay focused on your journey.
I want to learn ArchiCAD, where do I start?
https://blog.graphisoftus.com/transitioning/software-trial/i-want-to-learn-archicad-where-do-i-start
Conquering BIM: never do just one thing
https://blog.graphisoftus.com/bim-washed/conquering-bim-never-do-just-one-thing
New User Trouble: You don’t know how to click
https://blog.graphisoftus.com/archicad-education/tips-and-tricks/new-user-trouble-you-dont-know-how-...
There are only two reasons to do BIM
https://blog.graphisoftus.com/archicad-user/there-are-only-two-reasons-to-do-bim
Hope that all helps. I also highly recommend watching lots of YouTube videos. I link to some channels in the first post, but here's mine:
https://www.youtube.com/shoegnome
What I like about YouTube videos is it gives you a chance to watch people work, which is always super enlightening.