I've always made lists. Developing ideas, I've found lists were the perfect place to start. For me, they were always simple - likes and dislikes. I then would add things like locations I liked or found cinematic. I made lists of films I liked, then broke them down into categories and genres and plot types. Lists of novels, short stories, plays, musicians - everything, and once you see all these lists down on paper, it really helps to put things together. To get a new perspective on yourself and what you like and what the hell it is that you should be creating!
Below is an excerpt from an article I found on Brainpickings.org, in which Ray Bradbury talks about lists:
From his book Zen in the Art of Writing:
-- These lists were the provocations, finally, that caused my better stuff to surface. I was feeling my way toward something honest, hidden under the trapdoor on the top of my skull.
The lists ran something like this:
THE LAKE. THE NIGHT. THE CRICKETS. THE RAVINE. THE ATTIC. THE BASEMENT. THE TRAPDOOR. THE BABY. THE CROWD. THE NIGHT TRAIN. THE FOG HORN. THE SCYTHE. THE CARNIVAL. THE CAROUSEL. THE DWARF. THE MIRROR MAZE. THE SKELETON.
I was beginning to see a pattern in the list, in these words that I had simply flung forth on paper, trusting my subconscious to give bread, as it were, to the birds. Glancing over the list, I discovered my old love and fright having to do with circuses and carnivals. I remembered, and then forgot, and then remembered again, how terrified I had been when my mother took me for my first ride on a merry-go-round. With the calliope screaming and the world spinning and the terrible horses leaping, I added my shrieks to the din. I did not go near the carousel again for years. When I really did, decades later, it rode me into the midst of Something Wicked This Way Comes.
To read more on this, here's the link: