A quick couple of additions.
4.) I will respect those who entrust their work to me.
I planned to pen the usual "do right by the reporter" kind of thing here. Then my journalistic conscience spoke up. "Um, Clay," it said, "The work of many other people besides reporters passes through the hands of a copy editor. Why don't you mention them?"
The little devil had a point. Photographers. Designers. Graphics artists. Assigning editors. We handle their creations too. And we sometimes take it too lightly in the rush of the evening. We should consider the reporter's intent. We should consider the photographer's intent. We should look at the page layout and consider what the designer meant to do.
These folks all started the process. Now it's up to us to finish it with aplomb.
5.) I will know and use my newspaper's style rules.
Low on the list for a copy editing blog, I know. Perhaps we should think of the numbering system as separate from entries' importance. Whew. That's a relief.
Anyway. You should know the style before you use the style. Rules and guidelines are seldom absolute. They can be bent, broken or changed. But we should know when that happens and why.
As Will would tell you, style ensures consistency and readability. It differentiates a newspaper from a collection of stories thrown together. It is the voice of the paper.
Perhaps not its voice. Maybe its accent.