Go naked, no one will want to go near you if they think you're that hard core.
Try and get on the team with little kids on it, I did once on a stag do a few years ago and they were like fricking Ewoks. They won every game for us.
You should get a hood for over your mask, if not use a beenie, I wore a couple of pairs of shorts, it's painful if you get in the soft tissue of your arse, MTB gloves and a box are useful. Use a Buff for round your neck, if you get shot there they look incredibly like love bites.