I love concept art, BUT…
Most of the time you have to ask yourself, how much information do you need to get an idea developed. I like skribbling with a pen or pencil and sometimes it is enough to see where the idea is going… especially when its purpose is the written word of a novel.
I also use this technique for videos, thus creating rough storyboards. I always have to keep in mind that this isn’t about the drawing, but the final piece of work, the video or the novel.
One thing I do is to write annotations onto the drawing. Words, that remind me what the feeling should be like or what essentials are to be shown, like characters or locations… or sometimes the feeling of a piece of music.