Here's a way I do film scoring sometimes
Pick a synth pad or drone that matches the tone of the scene. Sometimes it'll just play one note/chord throughout the whole scene, or I might play a few different long chords. If I do have it change chords, I carefully time where those changes occur to match what's happening in the scene. Watch the scene again once with the synth pad.
Choose an instrument. Let's say piano. Record myself improvising piano over the synth pad while watching the scene. Watch the scene once and fix any wrong notes or major timing issues, but don't mess with what I recorded much otherwise.
Choose another instrument. Let's say cello this time. Record myself improvising over the synth pad and piano while watching the scene, trying to get any moments I missed with the piano, or want to double/harmonize with the piano for emphasis. Watch the scene once and fix any wrong notes or major timing issues, but don't mess with what I recorded much otherwise.
Repeat this with as many instruments as I want until the score feels as full as I want it to. Then go make and make any tweaks or edits that I think would improve what I improvised.
I get some really cool results this way, by reacting to the scene in the moment as much as I can rather than trying to plan ahead too much. I'm currently working on a cue this way, but unfortunately I can't share it just yet. But here are two tracks I made using this method, in two very different moods!
You can actually check one of them out in context here, starting around 6:10.