defeating alot of enemies
but really i wouldnt know how to help as i dont know your level, so cant suggest an enemy or spot.
some basic things would be to use those skills though, just keeping in mind high damage or upgraded skills or cutlass do more damage, thus limiting your potential rep gain.
or you could go the high damage and alot more enemies route, rather than "milking" by mistiming hacks and using taunt and brawl repeatedly, depends on your playing style.