Let's look at today's free writing session as a way to explore the emotions of a scene and more. Take a scene you're working on and decide what the central core of the scene might be. Say your heroine or hero first glimpses the person of their dreams. Or the detective sees a body of a murder victim. Or the fantasy protagonist comes upon the villain. This doesn't mean they come in direct contact with the opposing person but they see them.
Write down the core reaction of the character. Now what is happening to your character may not be something you've experienced exactly but you do have similar situations. Take that core and just free write down what you might be feeling. Add to this all the senses, What do you see. Just jot down the words. No sentences, just words. Is there an odor that you might smell. A texture you might touch. Sounds you might hear or the absence of sound. Do you taste something in the air.
Your word list might look like this. Remember what you remember from a similar situation in the past can be filtered through your imagination. This is something I often do when I'm writing mysteries. So here's an example.
Shocking discovery. Body. Dead. Smell. Urine. See. Orthopedic supplies. Cart. Potential weapons. Fear. Speechless. Touch. Body cold. Body war, How long ago. Who did this? Didn't like. Gossip queen.
I continue for ten or fifteen mintues. then look at all the things I've written down and suddenly the scene forms in my head and I begin to write. I have stepped into the character and become her rather than the observer from the outside. This adds emotion to the story and emotion is what your characters need to make them vivid to the reader.