I'd say: "Music, my boy! Music is the answer!"
I wouldn't be mistaken. If you have a picture of a scene, try capturing that scene in a song you trust that will hold that scene and whenever you listen to that song, that scene will pop up and you'll remember it. Greek epic poems (like the iliad and the odyssey) were sung, not told. And have you seen how long those things are? They lasted the whole night singing that for a wedding, birthday, etc.
That's what I do with my webcomic: "stereoaddictions"-
What I started with, when writing, was taking notes of everything I thought. I had to note them as pointers because I had to connect everything together. I find this less attractive and you'll probably won't enjoy the writing when you see a whole bunch of pages full of ideas that you must order and put them nicely to be read. It simply brings you down. You see the full picture and can't put it down on the format you want without raging.
Go step by step. Don't plan big. Just, have an idea of what would your characters do and RESPECT that. Everything else is just how creative you can get building scenarios.