If you haven't read the Bustamante breaking article, you should.
Also check out this post by Colin Colenso:
http://forums.azbilliards.com/showpost.php?p=239129&postcount=17
Take whatever will work for you, as far as power goes. Bustamante uses three or four things.
At the Derby City, I watched intensely some of the hardest breakers. The timing and coordination is something that if it's not natural, it would take some work. Again, add a few things at a time, and it could work wonders.
Elbow
There are two distinct power breaks that I've seen: Elbow Drop and Elbow Rise.
Elbow Drop Breakers: most hard breakers. For pros, this might include Bustamante, Sigel, Strickland, etc.
Elbow Rise Breakers: Archer, Breedlove, Lil John, Sparky Ferrule, Sarah Rousey.
In either case, the elbow drops, but since the Risers rise, the tip dips down on the back stroke, and shoots up on the final stroke. So, Elbow Risers aim at the center or a hair high on their setup.
For Droppers, most will aim low. Really low. Some aim right to the base of the ball or lower. Since they do this, and they get good contact, I assume the elbow is dropping before the tip contacts the ball.
Tip
Most of the hard breakers seem to be able to take that tip all the way to the bridge loop, often actually passing through it. This ensures the longest travel to get up to higher speed, without having to bully the stroke.
Backswing/Pause
I notice that most hard breakers take the final backswing relatively slowly, like they're drawing a bow. Players like Sarah will actually pull it back to the loop and almost freeze with her raised elbow high in the air. Archer also freezes with the elbow higher, but not nearly as high as Sarah's nor for as long a time.
Hips
There is definitely something to be said about rocking your hips back slowly on your final backswing and then leading with the hips on the final stroke
before you start the forward swing. Pagulayan is a good example of this. On video, this might cause you to think he's pausing his stroke because the stick stop at the full back position while his hips start their move forward. This is probably the most difficult timing transition. The hip lead is part of the aforementioned freeze.
Follow Through
A lot of today's breakers follow through by letting go of the bridge hand, and bring the cue forward past the center of the table (if they can reach). I don't know if this really helps, but the act of following through helps to not check up your stroke. I still follow through to the table like Sigel, but not so pronounced.
So, even if you do any of the above in small controlled doses, rather than the wild lunge like Breedlove or Sarah, it will add power.
Whatever you do, if you find the cueball going forward after hitting the rack, either lowering your tip at address, or raising your elbow during the backswing can prove helpful.
Fred