If you are using no weight, you might actually find it easier to get into form with some weight on your shoulders.
You may have the bar too high on your neck.
Get the bar comfortable.
tighten up-chin level-abs tight
NOW-break your hips. This is crucial.
You want to sit back not just drop down.
Staying tight--feel your weight
Now think of this as you sit--
load your heels
then drive back up through your heels.
Now don't do all this thinking under tension. Mentally you may want a few cues, but get used to the set up-the break, and the drive.