• Do more than state agreement or disagreement. Justify and support your opinion. The most persuasive opinions are supported by evidence, examples, reasons, and facts. If you disagree with something, say why. If you really like something that you've read, let people know what makes you think that way.
• Do the appropriate preparation, such as reading and lesson activity work, before you join the discussion.
• Read the Discussion guidelines closely and keep your comments succinct and fairly brief. A paragraph or two is plenty unless you are posting something that by nature has to be longer--a short story, for example.
• Check your post before you send it. Pay attention to your spelling and grammar, and be sure your message makes the points you want to make in a clear and concise way. Remember, other students and instructors can read your messages.
• Help move the discussion along. When contributing to a discussion, read other people's comments first. Introduce new ideas, but also build on what others have said ("Piggy-back" on other people's ideas).
• Keep up with the discussion throughout the course. After you have made your contribution on a topic, check back a few times to find out how the discussion is evolving. Does someone's comment make you think twice about your view?
• Share your experience with your fellow students. You may be able to offer advice to someone who is newer to the course.
• Respect others' ideas and opinions. Feel free to disagree, but express your disagreement in a respectful manner. Disrespectful communication is poor communication and not acceptable

Also see: Rules of Netiquette in Online & Distance Learning Courses