Yep, gotta agree. I play -- or have played -- piano, guitar, bass, and alto sax. As a result, I really don't have any issues writing for those instruments, but since I've never played drums, I just kinda fake it Talking to drummers has really helped clear up how to approach some aspects of percussion writing. Also, checking out videos of drummers on youtube has been really constructive. Watching videos of pianists may be helpful for you, but I'm not so sure how useful that would be on a melodic instrument. If I were you, I'd take the low road and just download some sheet music, see how chords are voiced, how the melodies are written, how wide the pitch intervals tend to be across both hands, and go from there. Also, a good rule of thumb is that most pianists can't play comfortably or accurately beyond a 10th (octave + major third), so don't write chords for one hand that require that stretch.
Tensei also mentioned not just shifting bar/block chords around. That's critical. While you certainly don't need to follow the "rules" of voice-leading, pianists almost never play two successive chords in the same voice.
You could always try writing your piece and sending a MIDI to a pianist who can check it for feasibility and make some corrections.