If you are a writer who has already written his/her first book and now looking for some good publishers or their book, then the first step you should take is to write and send query letters addressing it to a literary agent or an editor at a publishing house interested enough in your book and willing to sign you as a client, and, hopefully offers you a great sum of advance money.
A successful query letter has the following characteristics:
Ends in a single page — never longer
No mistakes — typing, spelling, punctuation, and grammar should be perfect
Gets to the point directly
Written on a quality paper
Positive tone and style