Use breathing exercises to relax your body and to free of your mind of all distractions, which lets you access your memories more rapidly.
Use "sense memory" exercises to help you connect with memories that invoke a particular emotional response. Obtain an object that has some meaning for you, whether an old photo of your family or a gift you received from someone you love. Stare at the object, and explore it using all five senses. Describe what it looks like, how it feels, what it sounds like when you close your eyes. Often, your thorough examination of the object will reveal powerful emotions from your past that you may not even realize you possessed.
Recall the emotions produced by a memory. For example, if you are playing a scene that requires you to act betrayed by a friend, you must think of a time in your life where you experienced betrayal and translate those same emotions into the scene. Do not focus on the details of the betrayal, but rather how it made you feel.
Perform a private act in front of a public audience, such as an acting class. Private acts are things you do when you are alone that you likely would not to if another person was in the room. They include dancing, singing off-key, cleaning your ears with a finger and talking to yourself. Performing these acts in front of others helps free you of inhibition, allowing you to become more fearless in accessing emotions, especially painful ones that you previously kept hidden from your work.
Use an imagined moment to access your feelings. If you can't connect with anger in your own memory or experience, imagine a situation that would evoke that emotion. For example, if you have children, think about how you would feel if someone hurt them and that person was captured and put in a room where you could confront him. Imagine the things you would say or do to that person, which connects you to feelings of rage and darkness that already exist inside you.