The Now.
Stop trying to achieve a clear mind. Stop trying to do it right. There is no goal. There is no purpose. In today's fast-paced, and goal oriented world, this is a hard thing to accept. To let go and accept that you are carving out time to achieve nothing, just to be.
"It's a kind of digging the present. It's a kind of grooving with the eternal now. And brings us into a state of peace, where we can understand that the point of life, the place where it's at, is simply here, and now." — Alan Watts
Meditation isn't done to create a benefit, to become "more" or "better" in some way than someone else, or even a "more" or "better" version of you, but to simply connect to life.
Whether meditation, as a way to be present interests you or not, be sure to slow down long enough to enjoy your present, and the people around you right now. The past, or future, version of people in your life, is only something that exists in your head. How they are right now, in the present, is all that is real. Do not be so stuck in your head, that you miss what you actually have.
If you are interested, here is an old Alan Watts recording that teaches meditation.
How does this pertain to portraits? Being present, and in the now, is the most important element in the creation of a portrait. Celebrating the most important thing in your life, your relationships, by visualizing and creating art, is a wonderful way to be present.