First off: There is a really loud clip at the start.
At 00:15, you've got a kick. First off, the kick isnt very punchy, and second, it needs more sidechain.
The snare also needs more punch. The chords sound very mellow. They need some OTT.
You can find great samples on Cymatics.fm for dubstep, and they are all free.
Nice job overall.