Film making terminology
Learn and understand the basic technical principles and terms of filmmaking. While it is nothing that you might need directly for your own work, it helps tremendously to communicate with people involved in the film project that you’re working on (most importantly the director of course) and even more importantly understand work processes and also get a feeling of how complex certain processes are during the filmmaking. It might be very embarassing if your director talks to you using technical terminology from film and you have to constantly ask what it is. In general, it leaves a better impression when you are informed about the things that you’re working on. Also, developing a more analytical view on the project that you’re working for might also help you to consciously see things that you wouldn’t have noticed normally and highlight them a little more with the music etc. One of the standard overview works of film theory is HOW TO READ A FILM by James Monaco which has also been published in several languages, but there are also a lot of other books on that topic as well.