Film/Game music composition is a great industry. If you’re good enough you will get jobs. Everyone wants to be a “film composer” or “game composer”, but the fact of the matter is 90% of these “composers” are not good enough and stumble at the first (second or third) hurdle.
If someone asks for revisions, do them. We have to remember it's their "baby". We may think we nailed a music cue or sound effect. But for whatever reason the client may not. It's their call :) Above all, stay passionate and excited about what you do! We truly are fortunate to make music and sounds for a living. Or, if it's not your living yet, you're still very fortunate to have your gifts and talents.
Always learn new things, deeply analyze music that you like and learn how to express emotions and ideas with music, preferably music that has your own voice.
Your education gets 80% of its value from you: the diploma isn't going to get you any jobs. Get involved, make connections, and participate deeply in your education or you'll walk out of school with nothing but a poster and debt.
Remember the value of custom content. There are so many ways of finding sound for your projects these days – but in my mind (and I might be slightly biased), there’s nothing better than using custom-created sound. It gives you material that’s created to exactly match your requirements and fit with your project and vision. It also gives you a unique brand asset that you can use going forward.
Never ever lose sight of why you became a musician first. Work in this business for any length of time and you’ll start to forget the reason for getting into it to begin with. That’s suicide, as far as I’m concerned.
As composers, creators, I understand that versatility in your writing is key. Mastering a variety of genres can only improve your chances of success in an industry that exists primarily with brief work. Saying that, make sure you take the time to be yourself.