This shot is as much about speed control as it is about being able to shoot fast. Practice getting the correct speed on the cue ball so it just makes it into the pocket. Once that's down, then work on adding the object balls. Start with one or two balls in each set. Then get up to three in each set and then build up the last set. On the last set, make sure you leave a little space in between the balls so each has a clear path to the corner pocket.
Some people like to fire the 1 ball in right away after hitting the cue ball. That's fine too, I just find it easier to maintain the same rhythm throughout the shot than changing it up. Also, figure out where it's easiest for you to look to ensure you're making the balls. Your eyes have to move back and forth quickly to get the right alignment, so it's best to try to minimize your eye movement.
I call this 11 Before 2 because I fire 11 balls into the pockets before the cue ball goes 2 rails.
2006 - 2017 © Tim Chin