Cleared twice so far, might try hard this week if my friends will stop slacking and get to 29. Communication is KEY. Bring more than enough ammo synthesis. Keep a level head, you're going to wipe, people will die, don't get upset about it or you'll end up hitting a wall of frustration and won't complete it. Do not bring a level 25. Sorry to say but they will be a hindrance with the last boss, if not before. Personally I think getting 5 other people to finish that damn Gorgon Labyrinth is harder than the last boss. Stay cool, learn to adapt to situations the second and last boss all require people to be able to adapt to situations when things don't go exactly right. Also don't bring anyone that will not talk. Sorry but if you don't have a mic or are "willing to listen but won't speak", you're not going with my group. There are many videos on how to do fights and strategies, but they may not work for your group. Learn what works for your group and stick with that. Those are basic but very important. I can't think of more off the top of my head but I'm sure there is more.