The main strategy is the one above posted by respectpays, but no strategy will work if the team don't follow it, and also players with GS below 14k will probably ruin it for everyone, as they don't have enough AP and CS to DPS or Life Steal to stay alive. On my FIRST Tiamat kill I got my Golden Dragon Grimoire off hand!…
I wish there was a Necromancer since it's a class more focused on pets (i.e. Skeletons, Golems, Zombies). Warlock is definitely NOT a pet class in Neverwinter, he is more cursed/energy channeling based class. But if we can't have a Necro, I'd deffinitely go with the Druid, simply coz druids are awesome.