Some writers create in a vacuum. But most artistic types need human contact, if only for reality checks. Writing groups and writing partners have been a foundation for my creative life for decades. If you don't belong to such a collaboration, consider it! It's nearly impossible to make serious headway as a writer without constructive feedback.
This morning, I met with one group of collaborators--all published, all dedicated in our different genres. We meet by conference call once a month and two of the four writers workshop their essays or chapters. The writer stays in the "writing box" during the call, taking notes and keeping silent, while the three others share feedback on the piece, read before the meeting. I always come away with much to ponder, excellent ideas for improvement, and vast encouragement.