In addition to Sankar, this community is a great place to learn and build relationships. People from all over the world are here asking and answering questions, and giving feedback. If you ask a question or post something, chances are someone will respond quickly, and you may even get more than one person to participate.
The Tableau Ambassadors are all great resources. Tableau Ambassadors | Tableau Software
Look for the Community Ambassadors on this forum - they're a great bunch who know a ton and love helping others! (You may check out some of these interviews to get inspiration/motivation from their Tableau stories: Community Canvas
You might also check out the DC User Group - Washington D.C.
I've posted here before on occasion, but I'm pretty forum shy. I also feel embarrassed about having very simple questions taking up space on the community boards. I'm kind of looking for someone I can be dumb with, lol.
I also feel totally inadequate to join a group of Tableau users, but maybe I'll check it out.
In case others have the same question about getting started with mentorship, I'd like to share the following resources.
I gave a co-talk with my mentor at TC18:
I wrote up blog post recaps of the talk: