Atma vichar is to meditate upon your atma. Our true identity is not this physical body but the soul that brings life to it. By focusing on the atma, we are able to remain calm and stable in extreme situations.
We spend our lives chasing worldly pleasures, trying to satisfy the desires of our senses. This false sense of reality is based on the misconception that we believe we are this body. The happiness we receive from indulging in materialistic objects is temporary, and in our constant pursuit of them, we forget that one day our bodies will no longer exist.
The goal of life is to be freed from the cycle of births and deaths, to attain moksh, and to permenantly reside in Akshardham, the abode of God. By separating ourselves from our body and realizing ourselves to be atma, we remain aware of what we must accomplish in life. Atma vichar should be done every morning as part of our daily puja.