Lying face down with your forehead resting on a mat, arms outstretched with your elbows at right angles, set your shoulder blades and when you are ready lift your head about a half centimetre off the floor and then lower. Continue to repeat this movement. Make sure that as you perform this exercise you are not tipping your head in any direction and that the back of your head remains long throughout. As you become stronger, you can increase the duration of time that you are holding the lift for.
When you are comfortable with this exercise you can add arm lifts to further challenge yourself. Make sure that as the arm lifts that the neck is able to remain long throughout.
Breathe normally throughout this exercise.