Mostly I'd rely on PD for the AR bonus and stick to using a dagger for your main attack (Diggler or Malice is a good choice.) Otherwise I'd go all +hp gear and stock up on resist charms (particularly lighting and fire) skills I'd put points into bone armor and bone wall with one point in clay, amp, weak, and IM). basically what you'll want to do is play very defencively and just get your stabs in and run and et the other players kill each other with your posion helping them kill each other, then once you get down to a few players stay back and become the second player on the one defening one (pick the ones that will give you the most trouble at the end ie kill the pallys and assassins first).
Most likely most smart players wont try to kill you first since you wont be precieved as much of threat, so use that to your advantage. Also if you can keep from cursing and targeting some of the weaker builds since they most likely will want your curses to help with the badder boys. If you can get it down to being one of the last 3 hopefully they'll all be melee and you can stab them both and then attack the one you think will win between the other two.
Personally I'd go with cleglaws for your gloves and try to stay out of combat but target those fighting that you want killed (mostly the assassins and pallys) so that the other players will have an easier time with them. Also try to cast you clay on those that are the biggest threat as well, the clegs and slow from golem can turn the tides on those that are typically the biggest threats particularily the chargers and kickasins (they wont be able to get enough room between) also keep them weakened if you can, then switch it to amp once you need to fight.