So with DRK, during your opener you want to be using two oGCD skills in between GCDs. As OT my opener looks something like this:

Dark Arts > Unmend (Plunge) > Scourge (Salted Earth + Carve and Spit) > Hard Slash (Blood Weapon + Dark Passenger) > Syphon Strike (Dark Arts + Low Blow) > Souleater

From there I continue into Delirium, maintaining Scourge as well, and using oGCD abilities as they come off cooldown. For MT my opener looks like this:

Dark Arts > Unmend (Plunge) > Scourge (Salted Earth + Carve and Spit) > Hard Slash (Dark Dance + Dark Passenger) > Syphon Strike (Dark Arts + Low Blow) > Souleater.

The only difference is Dark Dance in place of Blood Weapon. This is done to ensure that you will have your Reprisal proc at the beginning of the fight. With this MT rotation, you can easily pull 700 dps and even more once you get gear. For the OT rotation you're looking at 850+ DPS with your current gear. These numbers will increase even more once you get your Eso weapon.