I did this with my warlock and primarily using a void sniper. Just watch where other players with snipers camp and use those spots. Normally works best on control where you can snipe at the control points or from the control points while others come at you. go slow and don't rush into situations. It probably took me half a dozen rounds to get used to it, and I had a few negative rounds while I did, but after practice and getting used to the maps you should start racking up the kills. I had Atheon's epilogue and Truth, but after a few rounds of practice I was getting all my kills with the sniper and my nova bomb.