It's funny, when I write the first draft of a scene I find it often seems more like a radio play than anything else. It will be virtually all dialogue with a few essential movements thrown in. But when reading it back it's almost as if it's all taking place in a giant white room with nothing around the main characters.
That, of course, will never do. But yet, I need to know what happens in the scene before I can go back and add the finer details. So I let my first draft read like a radio play and then later I go back and throw in the color.
How do other people do this? Do you have all the details to start with or do you just write the dialogue you hear in your head (okay, I don't really hear voices or anything) and then go from there?