I was reading the pantsing versus outlining thread and thinking about my own technique, and I realized that one thing I do whether I'm pantsing or outlining is that I cast my major roles.
There's a folder with all my word files, strictly pictures of actors and actresses that I've picked out to represent characters in my mind. Everyone from famous Oscar winners to people from stock photos or hair-style websites. (I tend to stay away from really evocative performers, like, say, Robert Downey Jr, who bring their own personalities with them.) It simply helps that person stay vivid in my head.
Do other people do this? Would you consider it a cheat? The thing I like most about it is that you can describe that specific person if you want, in immense physical detail, and your readers would still rarely actually picture the actor you're describing. Unless they cast books as they read them, which is probably a thing.