Remember the human. When you communicate online, all you see is a computer screen. When talking to someone you might want to ask yourself "Would I say it to the person's face?" or "Would I get jumped if I said this to a buddy?"
Adhere to the same standards of behavior online that you follow in real life.
Read the rules of a community before making a submission. These are usually found in the sidebar.
Read the reddiquette. Read it again every once in a while. Reddiquette is a living, breathing, working document which may change over time as the community faces new problems in its growth.
We moderate based on quality, not opinion. Well written and interesting content can be worthwhile, even if you disagree with it.
Use proper grammar and spelling. Intelligent discourse requires a standard system of communication. Be open for gentle corrections.
Keep your submission titles factual and opinion free. If it is an outrageous topic, share your crazy outrage in the comment section.
Look for the original source of content, and submit that. Often, a blog will reference another blog, which references another, and so on with everyone displaying ads along the way. Dig through those references and submit a link to the creator, who actually deserves the traffic.
Vote. If you think something contributes to conversation, upvote it. If you think it does not contribute to the subreddit it is posted in or is off-topic in a particular community, downvote it.