First off its not a public search gametype like the strikes or crucible. So you need to create a group of your own that all players have mics and that are high levels. That is the most logical way of getting a great raiding fireteam. By getting people you know that are high levels with great gear or really high levels strangers with mics and NOT by inviting completely random people that are level 20 with no mics. Make a plan then go pursue it. No plan=failure