I like the composition itself. It's pretty energetic and catchy. I think the instrumentation arrangement needs a lot of work though. One easy change you can make to improve this quite a lot is to layer to brass leads, which tend to sound thin when played solo in one octave. Don't just copy and paste the melodies though, because as you move further down in the register, it becomes increasingly difficult for the instruments to effectively carry a melody. I think the percussion lacks much-needed power; it could benefit a lot from more cymbals, or maybe even a shaker or tambourine. I noticed many missed opportunities to slightly alter the instrumentation to create some subtle contrast between different parts of certain sections. For example, one common technique is to play a phrase with a string ensemble, and then the phrase is repeated but with woodwinds (I'm not suggesting you do this exactly, this is just an example to help convey my thoughts). This is a solid foundation but it sounds incomplete to me.