1) Bring a good attitude to every dungeon and your teammates. Yes even Aurum Vale.
2) Be courteous to your team. Greet them, let them know you're new if you haven't done the dungeon before. Ask for tips before the boss.
3) Don't just answer with "watch a video" the day when new patch content is released.
4) If someone is being a salty snowflake, feel free to "Imma stop you right there" and add them to your blacklist. Then they can talk to a wall.