my biggest problem is that most of them think they need to give instruction on how to do the raid, like they need to prove they know what's going on. Typically there is one or two people who are the raid leaders, let them do their damn thing, give cues and such, and not talk over them. Generally, that's the advice: don't try to talk over people, and don't try to lead the damn raid or give advice. Just be calm, be helpful, contribute when asked, and most of all, don't -blam!- up.