Options on high ball -
For a short ball I just move in and hit it flat/slice downward, just club the ball as another poster said.
For a deep ball, give ground and just rip it with a long looping swing with lots of topspin. It's like throwing the racket upwards and hitting at eye level is not difficult - think how Muster or Gasquet would swing on a high topspin forehand. These are both easy shots to hit. If I am near the baseline without a lot of time I can drive slice the ball which is easy or hit a drive going through the ball with a little topspin, but it is more difficult and more risky.