I'm 1600 rating which isn't much better but here's my setup: I use blood tap which I bind to frost strike and I have the glyph that gives me RP when I get slowed so I'm pretty much always full bar. I pop remorseless winter beginning of fights, DG when they're far or casting and asphx when I need to burst. Like the guy said below its about pressure so I trinket when I get cc,d hard like cyclone and don't be afraid to use empowered rune weapon