We don't give out advice, but here are some professionals whose blogs and books about book publishing etc. we recommend:
Please note that Leanpub is a self-publishing platform that is primarily devoted to encouraging people to publish their books while they are still in-progress. You can create a book anytime here:
Here are some tips we give to people who publish on our platform:
And if you really want to go deep into our publishing philosophy, here's our manifesto:
Good luck on your writing journey!