best way is to have a link for Soundcloud, which is by far the best way to present your music for libraries. The only problem is, you need luck and a lot of it as well. That’s what my experience is with music libraries so far. The guys are getting 1000s of emails a day, with music and whatever…and they just physically can’t answer you, because the % that they will hear your track is really low. The only way to go is re-sending the stuff, and say that you send an email a couple of weeks ago. The next thing is, the good and exclusive once are only looking for tracks, which are dead perfect. The highest standard of music production possible. I don’t know, how far you are with your productions (maybe you can link your Soundcloud here?), but the only way to go is just keep working on stuff, reference all the time and push yourself to the limits, work more, learn, fail, try again, quit for 2 weeks, stand up and start from scratch. Composing for trailers is the ultimate challenge, the standards are much higher than somewhere else. So getting into this field is like trying to climb the Everest for the first time. It’s extremely hard to get there, but you have to try, try and try again. It’s always a matter of time, when someone gets back and want to have your tracks presented by “them”. Don’t give up and keep sending your stuff out.
Good luck and best regards,