Summarize this article:

Make sure your fingers are pointing inward, and facing each other. While you move your fingers from the middle of your forehead toward your temples, apply pressure to smooth out the skin on your forehead.   Imagine you are sweeping away your forehead wrinkles. Don't be afraid to apply firm pressure. You want to feel some resistance from the skin while you perform this exercise. Now that you've completed one repetition, briefly rest your facial muscles. Instead of resorting to botox, repeat this exercise ten times every day to reduce horizontal forehead lines.  This is a good recovery exercise for the end of your workout. Combine this exercise with some of the others discussed in this article to more effectively reduce forehead wrinkles.

Summary:
Rest your hands gently on your forehead. Swipe your fingers outward across your forehead. Relax your facial muscles. Repeat ten times daily. Use with other exercises.