The guru's of the human potential movement always say, "Begin with the End in mind." In other words, know what success looks like and it will be easier to recognize the path that leads you there.
A book has three major milestones in its life. Most authors think that getting published is the biggest one, it is not. Getting published is just a milestone on the journey enabling the true objective.
The first major milestone in a book's life is the writing. Creating the work is the first major hurdle. You've probably already accomplished that phase of your book's development. You are to be congratulated at that accomplishment! This piece includes the editing and the polishing. The final product of this milestone is a work of literature that can be confidently passed on to a publisher.
Put it before them
briefly, so they will read it,
clearly, so they will appreciate it,
picturesquely, so they will remember it,
and above all, accurately,
so they will be guided by its light.