New level of perception and feeling should accompany it activating. Like tuning into others feelings scanning an environment, perceiving information. Focus on it when you are working to develop it, and balance it this with rest and development of other main chakras.

The most important thing to focus on is breathing. Saying that go with the flow.

If you can't feel warm and tinlgy then I think it needs clearing and cleansing. You could do this by focusing and meditating on clearing it. Inviting mineral energy in can help a lot. Burning sage or other incenses.

I suggest working with amethyst if you wish to develop and cleanse the third eye. And fluorite or kyanite if you wish to balance this with the other chakras, or with the heart chakra and heart chakra stones such as jade or fuchsite.