Balls frozen to the rail can be a problem spot for many players and they come up every single game. Isolate and master that shot here from all angles and you are sure to increase your run out percentage.
Start with balls only on the diamonds closest to the pockets.
Once you can run the full table start moving every ball a half or full ball off the rail. Note the difference in positional possibilities and potting angle.
Run one rail at a time without running into any other balls.
A touch of inside makes frozen to the rail shots much easier.
Once you can consistently make an up the rail shot, this drill is really about playing position, not shot making. Try not to run into any other balls and leave yourself a small enough angle that you can control.