The target is where the ball will contact the front, side or back wall after your racket, not where you intend the ball to finish. Every ball you hit should have a purpose, even if you're chasing it down under tremendous pressure.
The basic targets you should learn are 1) Serves, 2) Straight Drives, 3) Cross court drives, 4) Straight Drops and 5) Boasts.
You should learn to find targets in practice and see where the ball finishes. Every court will play a bit different, so in the warm up before a match, figure out the targets.
The Magic Spot - the top three feet of the front wall is always a great target. Try it out and see how easy it is to get outta trouble or keep your opponent in the back court.