In my opinion the change-up is the most devastating pitch in our game, period! Keep in mind I am referring to a good change-up, same wind up, same arm speed, etc. A great change-up is pretty difficult for most pitchers to master, with that in mind there are a pretty good amount of change-ups being tipped and/or the batter can see it coming. Hitting is so much about timing and what is more devastating to a batters timing than a well throw, well disguised change-up?. Picking the change-up is the best way to have a fighting chance, even when you know it's coming it can be tough to hit, remember that timing thing? Here it is... If you can't pick it and the pitcher has a great one, hit early in the count, or try to see if there is a pattern and sit on one. Many pitchers with a great one love to showcase it, just pay attention. If the pitcher isn't overly fast try this with two strikes, look slow and adjust fast, this does not work very well with pitchers throwing gas.
Sinking, staying back and holding your bat angle is a great way to give yourself a chance once you've committed to the pitch and are fooled, easier said than done!