Agree whith rolandps.
1. your best choice cc and slow buff uttilities (like enhanced paralytics and mutilating shard's). 25% AoE buff will be good
for enemies like mercs, their responsive safe guards can absorb only single target dmg abilities.
2. Remember mobilitty ana evading - this key to survive for PTs.
3. Your best friends - healers and DoT based classes in team (mara ani, merc pyro, sniper virulence, oper. lethality - they all applied the assailable debuff on target that gives 7% dmg to target; remeber all of your attacks is elemental based).
4. Remember colto overload 1 of your best def utilities, this abilitty reduce dmg taken by 30% when active and can keeping by 1 min and trig the abilitty when you low 35% in this spec.See on dicpline tree.
5. Don;t forget you can put crazy AoE, dot spreading whith deadly onslaught and flame sweep.
6. My opinion - find friend healer, pyro class its teamliked. But in unranked wz its fine too.
7. Taunt and mass taunt your best friends too. Use by CD on enemies that try to kill your teammate, bring them pain.
Remember if you choose pyroPT on PvP, you choose hard way but you will be rewarded greatly:)