Photorealistic painter Robin Eley makes incredibly life-like pictures of people distorted by the wrinkles and folds of transparent plastic sheets/bags. In this progress video of his 2011 work Plastic you can see that his strategy is to simply paint every change in value (the lights, darks, and mid-tones) no matter how small they might seem. Every highlight and every shadow make their own unique shape and like pieces of a puzzle or the sections in a paint-by-numbers they come together to make a clear image. What might be the biggest obstacle to you painting in this way? (Mixing the right tones? Seeing the right highlight and shadow shapes? Making all the shapes fit together correctly?) It is only through practice that we learn to truly SEE.