QUERY LETTER vs. COMPLETE MANUSCRIPT
As you get better acquainted with publications and editors, you will find a difference in preference as to how they want to be contacted by you with freelance submissions. Some publishers want to see only the completed manuscript, some want only a query letter, and others will take either. It is important to know what each wants and abide by that preference.
If they want a completed manuscript, send them something that fits their publication as exactly as possible. That means it is the right length, the right style, an appropriate topic and the right slant. A publisher will know immediately if you have done your homework and are sending them something that matches who they are—or if you have chosen them at random or as a last resort. Realize, however, that even if you match the criteria exactly you may still get a rejection. There are a lot of reasons for rejections that you have no control over, such as their being overstocked, having recently published or accepted something similar, overdrawn budgets, etc. But even rejected manuscripts will be noticed if they have all the hallmarks of an appropriate submission.