Part of research is knowing the editor you are targeting. By dedicating a file, a page in a notebook, or a folder in your filing cabinet, you can build a profile on the editor in your target market. Common sources for gathering your information include:

Notes from conferences

On-line writing forums

Interviews

Industry news

Critique groups

Your own rejection (and acceptance!) letters

Record everything you learn about the editor, from his or her likes and dislikes in terms of themes, word count, style, characters, and the types and names of books he's edited to his personal interests and even where he lives.

This information will not only help you target future manuscripts better, but it will enable easier, more personalized communication, whether via writing or in person. Once you find a common ground with an editor, you and he will begin to know (and remember!) one another as more than names on a paper or a face in a crowd... but as people. And as we all know, this business is often about connecting and networking...as people.