They need to know how to use their position the right way, and not abuse it. They should be friendly, and use proper grammar if you are looking to have a professional board.
1. Use correct grammar (Get a spell check if you're lazy). 2. Obey the rules you enforce. 3. For every time that you are mean (you will have to be sometimes) be nice three times. 4. Don't go on a metaphorical killing spree by banning everyone. That's not good.