They can't be afraid to call someone back for confirmation of facts. They need to understand language and grammar. And most of all, they need to be open to revision. I tend to put a lot of faith and trust in people, and this has often caused me problems. Investors pull out.
People find other jobs or misplace payment invoices.
The key is to not lose heart. If you get burned by one company or person, learn from it and move on. Having been an editor, I know how difficult is it to work with hundreds of writers and to put out a daily publication. Understand how busy editors are and try and offer them as much assistance as you can. Follow submission guidelines.