I've studied up quite a bit on the break shot. and these guys are right for the most part. Keep in mind it's just another shot, even though it's most important.
Good/same preshot routine. - stair down the rack, and exact spot you want to hit the head ball.
Hit half to full tip above center. - I have found that by adjusting your bridge hand to the correct height, so that when your cue is level it hits this spot naturally, helps tons!!!
Stay down throught your shot. - It looks like Shane rises as he pulls the trigger, but he only starts to move after contact with the ball. Leveraging his body through the follow through.
Hit SOFTER!!!! - Don't hammer away at the break. Less power = more control usually. I find that when my break is out of whack, I take some power out. If I still cant range it in, I move more to the center. YOU SHOULD BE FOCUSED ON CONTROL, NOT POWER!
MOST IMPORTANT ~ PRACTICE, PRACTICE, PRACTICE!!! - atleast once a week (usually more) I practice my break shot only, for about half to one full hour. It is the only way you will get that good break down consistantly. I almost never dry break 9 or 10-ball. 8-ball can be a little more tricky depending on the table. Some times I'll even go second ball break, most of the above will still apply.