Jake Mactire, author of M/M cowboy stories, says to edit, edit and edit again.
Make certain it's in the format the publisher wants prior to submission. Also get a group of beta readers, people who will be honest, and listen to what they say. It can be a bit hard to keep from being defensive at times, but by listening to their viewpoints, you will ultimately have a stronger book.
The final decision is yours as the author, but sometimes you have to cut something you just love but everyone else just hates.