A key mechanism used for opening a chakra point is by bringing your attention to the physical trigger point or Kshetram. By attending to this location in the body (the kshetram), one generates sensations which then travel back to the chakra, to stimulate and activate it.
The trigger point for the Third Eye is slightly above the middle of the eyebrows. So very close to the center of the forehead. The following technique uses this knowledge and other aspects of yoga pranayama to help you open this chakra.
8. Now visualize inhaling through left nostril and exhaling through right nostril, again the air is White Light and flowing in this triangular shape. Coming from the left nostril to the center of the forehead and then leaving the Third Eye and flowing out the right nostril.