1) Be kind to your fellow roleplayer. A wide ranger of roleplayers means a wide range of characters and skills. Even if you think someone could improve, try to tell them nicely.
2) All replies must be at least one paragraph long. Length is key to a good response because the longer a post is, the more a character is developed. Also, try to use proper grammar and spelling. If you are unsure how to spell a word, look it up or do not use it. The one time spelling is no issue is if a character's dialog is written to match an accent. Finally, no text talk. That gets annoying unless the character is sending a text.
3) I allow open threads. I also believe that no roleplayer should feel abandoned. If you have no threads with a roleplayer and they have one open, pick it up.
4) Profanity is alright by me without a warning but make sure that the person you have the thread with finds it alright. Profanity includes cursing, violence, drinking, drugs, and sex.
5) If you are going to be away for a while, let someone know. Nothing sucks more than getting a good thread going and then a person involved disappears.