First of all, you need a tarott deck. The first exercise may take up as long as you like.
Right. Get you're tarot cards our and shuffle them, and when you have shuffles them pick up one card. Look at the card what do you see? What type of scene is it? What does the card mean to you? Let the card tell you what its trying to tell you. Don't try and see what it means. Don't try to read it. Just relax and look at the card and notice the feelings you get and thoughts that pop into your mind, once you have done that, pick up another cards and study.
Hope it helps