Sharpshooting is so absolutely crap. Rocket Launcher should be obtained ASAP, so you can use a Multishot, Arrow Shower, Rocket Launcher combo. After that once you get Wolf Rush you have the completed basic setup which would be Acid Arrow(Minus 10% def to mobs) ->Arrow Shower->Mulitishot->Wolf Rush->Rocket Launcher
You want to wait about .5 seconds before you use Rocket Launcher so taht they fall down...
Basically it's Arrow Shower to keep them in place for Multishot, then Wolf Rush to knock them over, Rocket Launcher after they're on the floor to do some nice damage, and if they're still up, another Arrow Shower.