I recently had the opportunity to work on a short film project and though not my first film, I was reminded of how different working with a film director is from working with a video game producer. Though both need music, the approach that they take in achieving this goal is quite different and can be jarring for the composer used to working with one or another.
In general, film folks are often on a more intense deadline. This is because, with rare exception, a film maker regards music as truly a "post production" problem, and thus it waits until the end to get resolved. Often at a point where there is almost no time left to think sanely about the music as the director is working closely with the editor and other post crew to wrap things up as quickly as possible!
Here, however, I'll present a couple of bulleted tips about what composers find useful (and point out some things that are NOT helpful!)
1. Do a Spotting Session. No, this is not optional, no matter how busy you are. It is critical for the composer and director to have a time to talk about the film's total artistic vision. An equal number of scores have ruined a film as well as saved it. It's important to hear from the director the different moods he was trying to achieve for a particular scene as well as for the overall piece. A shortcoming in acting, sets, lighting, and other blunders can often be smoothed over by well crafter music playing an additional "character" in the film. However, without knowing these things, a composer may mistake a scene for comedy when in fact it was meant to be dead serious. (!)
2. Understand what SMPTE/Frame Rate, BITC, STEMS, BIT RATES and other technical audio things are before chatting with your composer. They will want to know these technical audio questions about your film and how you want your audio delivered. Not understanding these things just wastes time as you composer is required to explain these things to you. If you have a film editor besides yourself or (gasp!) a music editor - these people would be good folks to introduce to your composer and can probably answer all these questions.
3. Your composer will likely produce a rough pass for you of a cue or maybe your whole film. This is a rough take - to make sure they are getting the "feel" of things. So don't get too hung up on timing how "real" it sounds and so forth. If you are "auditioning" a composer and they are doing a cue for free, make sure you ask them to make a "final" version of this cue before agreeing to pay them. For their sake, don't make this a LONG cue. You want to basically test the skills. They are confident that they have what it takes or they wouldn't be doing this for free for you. However, it is certainly your choice if you want to ultimately hire them, so don't make them work for free for long before making your decision! If you have the budget to have your composer hire live instruments, they will likely not waste time on a good "mock up" for you since the live will sound infinitely better anyways.
4. Another note on live orchestra/players. Be sure to discuss this early on. Some composers write scores in a way that makes it very, very difficult to translate their score to printed music that could be recorded. Others (like me) write this way all the time so that its relatively easy to output to a fixed click and so forth. It's good to check with your composer to see if this is even a possibility and a skill they possess. It is a unique set of skills to translate what on one side could be improvising (however well) at the keyboard to your movie and on the other hand being able to translate these doodles into real scores that other humans can interpret and play in perfect sync together.
5. When you get your drafts from your composer speak to them in emotional language. It is certainly okay to say "Oh, I don't like that timpani there" or something specific like that, but most of the time, we are more interested in knowing WHY you don't like it there. It is very easy to misconstrue a comment about an instrument and think its the timbre of that instrument when REALLY you feel it wrecks the MOOD of the moment. In fact, that instrument may be fine, but perhaps a different register or rhythm is called for, or maybe its too loud. Your composer should be a good artistic collaborator and may have some genuinely interesting solutions to the problem at hand to help you achieve your vision, so give them the benefit of the doubt about how to fix something.
6. Be realistic on fixes. For many of us, it takes about 2-4 hour (depending on style, orchestration and many other factors) to write and produce about 1 *MINUTE* of quality music. So, if you decide, all of a sudden, that you ARE after all going to include those extra four minutes of the kids swimming with dolphins and want an awesome montage sequence that will be fully scored and oh, could we do that by tomorrow because we premiere in three days... well... no. That's crazy. Sure, it can be done, but it will be very rushed and your composer will be very grumpy. Unless, of course, you are paying them lots and lots of money. In which case it will be rushed, but people will probably not be (as) grumpy.
So, to all my film director friends, I hope you find these couple of pointers helpful. If any other composers want to comment and add to this list. Please do so!