Dude it's cool, I remember first trying to figure out the gaits too, it's tricky sometimes. First you should probably figure out which gaits she has, I'm not familiar with gaits all that much outside the rack. Racking Gait
That helped me out a lot starting out.
Now... what works for Indie and I
(so I'm not saying it'd work for everyone, but my personal experience is what I got to work on here.), is pretty simple. I ride in either a full cheek snaffle, mechanical hack or a halter. When asking for a rack, I sit up in my seat a little more- more on my crotch than you usually would for western. I then stiffen up the reins a bit... not TIGHT, but enough so I can conversate with Indie a little better (and not riged either, I keep a motion with her head so that I am not constantly pulling.). Once I have her attention, I nudge my heels into her side until she starts speeding up, I then collect the reins and hold her back just enough to soften her into the rack. Once she is steady in the gait I loosen the reins back up and let her have free motion of her head, however for Indie I have to keep a reminder with my heels occasionally bumping her into speeding because she likes to be lazy and slow down on her own.
The most difficult part is keeping the rack going, specially if the horse isn't used to it for long periods of time. After season breaks, I find that I often either have to slow down, or speed up mid-Rack to keep it from going into a bone jarring trot.
Once you learn the movement of your horse and their patterns- catching them breaking the rack and into a trot becomes easier and you can correct it before it happens.
I always like to reward a well done and consistant rack with a break, but that's just me personally x)
I do hope that helps some.