It's a good idea to start or join an ensemble. (I play viola (fairly badly) but it's one of those instruments always in demand.) Or get involved in the administration, so you can get to know the people who run the thing then get your things played, limited by the ensemble itself.
One tip: be VERY sure of your score, what you want it to sound like - especially if someone else may be conducting it. I've seen too many embarrassing moments where it's obvious that the composer didn't know how their work should be played. As applicable in an ensemble you join as one to whom you've submitted scores if the outfit is prepared to play it. Make a mock-up, get your score and conduct it at home until you know every entry, every nuance, etc. and get some tips on conducting.