Read all the messages people leave on the talk pages of articles you are editing.
Be polite, and discuss article content rather than editors. Do not make personal attacks.
Always sign your posts on talk pages using four tildes so that others can follow who is saying what. Put ~~~~ at the end of your message (not in the edit summary box).
When you intend comments for a specific editor, leave a message on their User Talk page (with a link to the comments, if the discussion is happening on a different page). That way, they'll get a notification about your message.