Your body must be relaxed. This can be done with yoga or other exercises, a hot bath, deep breathing. Lighting incense sometimes helps. Do whatever relaxes your body. You may also find it helpful to use an object to fixate on when you are beginning meditation.
Candles work well since the flicker of the flame requires concentration.
Empty all thoughts from your mind so that all you can see or think of is your object and your breathing. With each breath in tell yourself that your are breathing in the energy of the Universe. Breathe out the stress and relax each muscle of your body beginning at your feet and moving up. Do this until your entire body is deeply relaxed. Then begin the movie in your mind, repeating your affirmations as it plays.