Cinema Sound Systems Surprises
Unless you get a chance to listen to your score in a mixing cinema when doing the film mix (which is usually something only higher budgeted movies do) you should be prepared for your music sounding quite different in the cinema than it sounded in your studio.
The size of the room in a cinema has some effect on the overall acoustics compared to a near field monitoring situation as you have it in most studios. Whenever you have the chance, you should attend the film audio mix when it’s done in a mixing cinema to be able to take some influence on the sound in case you don’t like it.
And even though it has gotten better over the last years, there can still be quite a bit of difference in sound within different cinemas. Most bigger cinemas nowadays have a quite good sound (as there are also standards that need to be met) but some of the smaller cinemas will be having some older sound systems where your music (and the sound in general) sounds horrible.
So be prepared as a composer to sometimes be unpleasantly surprised about how your music actually sounds in the end.