Alright, everything below this is purely a JOKE. So please (please!!!) don't flame me. I already posted this under miscellaneous.
Ok here's the cheap trick to writing for a virtuoso. Take any simple children's song (and i mean SONG, ed...) like for example, Humpty Dumpty. Now, between every melody note, add a gajillion notes of the same chord. I recommend 7 for starters, 15 if you're writing for Horowitz. 31 if you're writing for Cziffra. Repeat for left hand if attempting to topple Islamey.
Add an accent to the melody notes. Done

Any other cheap tricks? Like say... double the tempo...