Episode 40 of The Happy Writer deals with finding a community of fellow writers that is useful to you.
Some writing and marketing books that have author communities attached:
Help my Facebook ads suck – Mal Cooper
The Indie Mindset – Adam Croft
The Indie Author Unleashed – Robert Ryan
Advantage – Joe Solari
There are far more of these, of course. Feel free to comment with extra communities based on books.
Listen to this episode on Bookfunnel or Youtube. NEW! The Happy Writer is also on your favourite podcast app!