Can you recommend any useful books or websites?
The following are very perceptive and knowledgeable about the book industry and contain advice on getting your work published:
Thinking Like Your Editor: How to Write Great Serious Nonfiction – and Get It Published by Susan Rabiner & Alfred Fortunato (Norton, 2003)
From Pitch to Publication: Everything You Need to Know to Get Your Novel Published by Carole Blake (Macmillan, 1999)
The Writers’ and Artists’ Yearbook (A&C Black, published annually)
The Writer’s Handbook edited by Barry Turner (Macmillan, published annually)
So Many Books by Gabriel Zaid (Sort of Books, 2004)
The Forest for the Trees: An Editor’s Advice to Writers by Betsy Lerner (Riverhead, 2000)