I think there are some things that younger composers should know. Showing up and walking around ACDA reminds me of some of the rules I use. Here are a few of the guidelines I use. Take them and make a list of your own.
1. Unlike the cutthroat world of pianists, most composers are really nice and supportive of one another. Normally, we are all doing something so unique that we are not trying to do anything except promote each others music. Come talk to us. We are nice and not very bitey.
2. You will always feel a little insecure and jealous. Get over it. I've had more success than some. I've had less success than some. No matter how much or little success I've had in a year, I always feel intimidated by other composers. Part of it is the age that we live in. There are literally more people writing good music now than have ever written music before. There are also more people writing filthy crap than ever before. The path is treacherous. No matter how successful or unsuccessful you are, if you are comparing yourself to others, you are not in the right place. To cure this problem, refer to rule #1 and come talk to us.
3. All conductors are assholes.
4. Conductors are nice people, and if you don't make friends with them, your music won't get performed. Every ensemble performance of my music has happened because a conductor took an interest in my music. Every commission I have received, from orchestra pieces to solo pieces, came from some single person taking an interest in me and my music. So, make friends. Play nice, and do what you can to promote their efforts. If it doesn't work out, you can always remember rule #3.
5. You have to promote your own music. Many of my teachers said this, but the reality is more complex. Composers are as diverse as any other group of people. We have our introverts and extroverts. One thing that is universal is that we all tend to spend a significant amount of time alone. That practice is not always conducive to the skills needed to promote and market music. For me, walking up to someone I don't know and saying, "Listen to my music. It's really good" is a hard thing to say. I do believe that my music is good. I do believe that people should listen to it. Since I have a harder time doing it myself, I usually attach myself to someone else who will champion my work for me. I make sure to walk around with someone who will say, "This is Kurt, and you really need to listen to his music." That one sentence is enough for me to get over some barrier and start talking. Figure out what works for you.
6. If you are "waiting to be discovered", you should learn about a new invention called the internets. It can help you get discovered a lot. It doesn't work by itself. Basically, it's a series of tubes. You put your music into the tubes and you get famous. The trick is, as always, figuring out what the right tube is for you.
7. Robert Sirota, the composer who was formerly the president of Peabody Conservatory and the Manhatten School of Music attends the church where I am the music director about 3 times a year or so. He comes to visit his grandson. We chat because he is a genuinely kind and encouaging human being. A few months ago we were talking, and he said, "The main thing is, you have to keep writing. It's easy to get discouraged and just stop writing. If you are a real composer, you have to keep writing. I think you are a real composer." So, keep writing, and also say something as kind as that to one of your fellow composers that you like. With the tremendous existential courage that composing requires, the best thing you can do is say to a composer, "What you have done is meaningful to me."