Don't play loud music in the background. No matter how great your tunes are, nobody else wants to hear it over the game. Especially don't set your mic right in front of the speaker so it is blasting everyone. If you do, I will do the same thing, but you will get the pleasure of listening to the Carpenter's "On Top of the World" over and over. Not because I like it, but because I know you will not. I don't care if I can mute you, I shouldn't have to especially in-game. Mute it when your little brother, little sister, nagging wife, and bitching mother are yelling in the background. Unmute it when your hot girlfriend is going down on you while you are playing, but only if you aren't vocal or noisy during the act - no one wants to hear you moan, it's creepy. If no one knows your voice, identify yourself, don't just answer "me". Use the system to adjust your mic volume, If it is blasting red, then you are also blasting others ears or crackling speakers. Don't have the mic so far away from your mouth that it sounds hollow. Conversely, don't chew on it or breathe heavy into it. Take it off when you go take a dump, or at least mute it. Yes, the rest of us are jealous that you can play and defecate at the same time. We don't want to hear it. Call out issues or needs in game before it's too late. Otherwise, don't bother saying anything. Fun-spirited trash talking is ok, don't be a douche about it. If you sound like a girl or a 12 year old boy, don't take offense if someone calls you one. If you join an open party chat/fireteam, say hi and ask if they have room for you, don't just assume that because it was open, that you are welcome. If they need the space for a friend they will certainly boot you, if they don't and you ask, you may just get to tag along with a good team.