Direct your attention inward. Have a look inside yourself. What kind of thoughts is your mind producing? What do you feel? Direct your attention into the body. Is there any tension? Once you detect that there is a low level of unease, the background static, see in what way you are avoiding, resisting, or denying life—by denying the Now.
Eckhart Tolle
Source: The Power of Now : A Guide to Spiritual Enlightenment
...pain is what it took to teach me to pay attention. In times of pain, when the future is too terrifying to contemplate and the past too painful to remember, I have learned to pay attention to right now. In the exact now, we are all, always, all right. I am breathing in and out. Realizing this, I began to notice that each moment was not without its beauty.
Julia Cameron
Source: Artist's Way: A Spiritual Path to Higher Creativity, Pages: 54