When you clutch is depressed, you don't need to push down the accelerator. So it goes a little something like this:
Accel (1st)
Clutch (as the clutch goes down, your accel should not be depressed and your accel foot should be coming up if not already up by the time your clutch is depressed and engages)
Accel (2nd)
Clutch
Accel (3rd)
Clutch... lol etc.
Like the others said, it's a little tricky in the 370z. Also, the clutch spring I hear helps and practice makes less practice.