So here's something I figured out recently. Many times I'll be trying to write a piece for brass, either for a competition or for school or something, and I won't have any ideas so I'll just take a piece I wrote for orchestra (many of the ones I've already posted here on NG) and just arrange it for brass. It usually turns out ok but I'm never really satisfied.
But if I write a piece for brass first it comes out much better. Then when I take that piece and make it for orchestra it gets even better! More meat is added to it, you know? Anyway enjoy!