Generally speaking, unless they have specifically asked you to do so, you should not send your work to other authors for comment.
First of all, authors are busy people, with deadlines to meet. Even if they have spare time for reading, they will have a backlog of material which probably amounts to several bookcases. Since your work is not the final polished article (if it was, they could buy it and read it at leisure), there will be lots of mistakes (spelling, grammar, continuity) for them to work through before they can even begin to enjoy the story.
Secondly, your plot may be similar to something the author is already working on. In fact, given the limited number of truly unique plots, and the fact that you probably enjoy similar types of literature, there is likely to be at least some level of overlap. This puts the author in an awkward situation: if they read your work and then publish something similar, they open themselves up to claims of having stolen your ideas. Even if these claims are false, they can cause resentment and possibly even derail book or film deals if the authorship is in doubt.
Workshops and reading groups
- A Primer for SF Workshops - 'No one can attend or comment who does not bring a story' seems a bit harsh.
- Fantasy Author's Handbook
- Neil Gaiman - FAQs
- Book signing etiquette - Trudi Canavan
- Most writers earn less than £600 a year
- Top 10 tips for being a best-selling author
- How We Automated Our Ebook Builds With Pandoc and KindleGen
- Write a Book with Markdown
- How I wrote my book
- Academic Markdown and Citations