Dynamic Shaping of Sustained Brass
Brass instruments have the greatest timbral change over their dynamic spectrum. Therefore swells, crescendos, sffz, fp are highly dramatic and very effective on them. If you use long sustained brass chords or tones on key parts of your score, consider giving them a dynamic shape (hitting hard, dropping to soft immediately (sfp/fp) and crescendo again). This will add a lot of livelyness to your composition.
It also helps tremendously to create more claritiy in an arrangement. Not having sustained brass at a high dynamic play over the rest of the orchestra but instead of them dropping away for a while after the initial attack gives space for the remaining textures to be heard. These strategies also help sample mockups to sound more real and lively.