Fattening up Arrangements

[spitllama]

The thing I've always struggled with, and that Bespinben could always do effortlessly, was really filling up songs to include voices that don't even translate well on piano. 
Take his arrangement of Dialga's Fight to the Finish as an example. By measure 24 he's imitating the stinking snare drum! HOW DOES HE DO IT

This problem has found itself in a lot of my arrangements, but a current example would be Phantom Ganon from Wind Waker:

Does anyone have some tips?

[Olimar12345]

That arrangement was awful...

Anyway, as for tips, try to transcribe as many voices as possible. That way, when you're arranging it for piano you'll have some extra material to fill the space with.

[spitllama]

That's the thing though. Usually I can't even make out what those voices are. Like in Phantom Ganon, they're so muddled that it's like background nonsense. Anything I can actually hear and make out, I'll put in.

[Olimar12345]

Concentrate on a single instrument, or timbre. Focus only on what it does(be it the melody, the bass line, or other) and try to ignore the other voices . If you can't, then start with something simpler.

[Greg]

I actually use Windows Media Players' graphic equalizer to bring out certain voices and tone down others. It might help you in this case.

[Brassman388]

Know your theory. In most if not all cases, simply knowing the bass and the top notes can really determine what the filler usually is.