Back in 06' I read a article on a old blog giving advice on having a good gaming experience with your guildmates.
These rules are what i've still stuck to even now and I thought I would share them with you.
1. Be intelligent -- ask questions to gain understanding; better to ask and learn than to not ask and never know.
2. Be mature -- act in a respectful and civil manner, towards guildmates and towards others. Do not taunt opponents, even if they taunt you.
3. Look forward -- do not despair over a loss; instead, focus on analyzing it to better understand and improve your gameplay.
4. Lift others up -- encourage and motivate your guildmates -- do not assign blame for losses and liberally share credit for victories. Do not criticize, instead offer suggestions as to how to improve.
5. Communicate -- If you have an idea for a strategy, say it. Don't assume others know something if you have never told them. Make sure everyone is on the same page before attempting a strategy. Be creative in strategizing and disciplined in execution.
6. Be friendly -- Be a nice person. Be helpful. Offer advice and support to your fellow guildmates. Help each other out.
7. Have fun -- Enjoy yourself. If you're playing a game, you should be having fun. This is not a job, this is a game. This is not saying that you should goof off while everyone else is focused on winning the battle; rather, it is to say that you should be having fun being focused on winning the battle.