- K.I.S.S - Keep it Simple Stupid. Post lengths that are unneededly lengthy, characters that are unneededly bloated, complicated plot lines so confusing it hard to follow them. A lot of people think Unique or good means overly complicated. If it takes a sentence to say something, say it in a sentence. If it take a paragraph, say it in a paragraph. If your character has so much stuff thrown into them because you the player thought all that was cool, it's going to be hard to follow. Same with plots. K.I.S.S - best thing I ever learned in English Class.
- Show me, don't tell me. One thing that bothers me about RPers sometimes is they'll come in and tell us how are characters are supposed to respond to theirs based on something in their profile. That we're supposed to think they are extremely charming, or extremely intimidating, or an extremely good fighter. Then of course, they get frustrated that people don't respond in such a way. I would much rather you show me through your acting and roleplaying ten telling me right out the gate then get mad when it fails.
- Don't take OOC talk personally. This is a huge one for me, since my guild likes to comb through characters decisions with a fine toothed comb and talk about whether or not what they made a good one. One thing I really like about the people I rp with is that they will talk about the negative aspects of a character along with the positive, never throwing out "Yay your character is so good!" for no reason. I think this helps us keep the OOC/IC barrier intact, we're able to criticize character decisions without criticizing the player for playing them. Some people take this as a personal attack however, unable to see that other characters would see theirs in a negative light.
- Don't be afraid to let your character lose or get hurt. As a GM this is vital. So many people will get really pissed off really easily if it looks like their character is going to lose or something happens to them they didn't anticipate. It doesn't even matter if you warn them something is coming first, when it happens some people will still get upset. I like working with fluid people.
- Don't take lore talk personally.
- Be interesting.
Plus, everything A'rklonn Sargonnai said.