Forget grouping. Stay as far away from other federation ships as possible. The fewer federation ships around you, the less likely they'll die too when your warp core explodes.
PVP Power Selection is important. Pick AWESOME abilities like Beam Overload, Fire at Will, Emergency power to Auxiliary, Tactical Team, etc. Don't forget to use these powers as often as possible.
Make sure you charge into large groups of Klingon players by yourself, without backup.