Basically, exactly what +fireamx said.

When I'm "power shifting" , as soon as I make a shift I'm preparing for the next. My foot isn't really on the clutch all the way, and I don't push straight down, It's more like a diagonal motion so I get just enough clutch to release pressure on the gears and then my foot slips off the pedal. My hand is never really "around" the shifter, basically I'm just "palming" it and either pulling straight down (1-2 , 3-4) or pushing away on an angle (2-3).

Another key to making this process work in a Crossfire is making sure you start this whole motion about 5900 RPM. You're right at the top of the HP curve and when you shift it puts you right at the top of the torque curve.

Done properly, you'll never hit the limiter and just get a very little amount of spin on the 1-2 shift. The above procedure works great on a prepared track surface, but is all out the window on the streets though where traction is an issue.