To form a psi ball, feel psi energy and concentrate it between your hands, forming it into a round shape. First, rub your hands together until your palms grow warm, then separate them, continuing to feel the energy between them as warmth. Pulse them toward each other and feel the differences in the bounce, until you begin to feel the energy build up, then round it out.
As you concentrate on energy between your hands and pull them apart, the energy is naturally flowing out. When you squeeze them together, you are concentrating that energy. Feel the resistance of the energy as you compress it. This energy flows through you, but make sure it does not flow from you. Instead, as you form the psi ball, draw energy from the universe around you. Otherwise if you are not properly grounded, using your own energy to power the psi ball can be draining, leaving you tired.
Visualization is the key as well. Visualize the energy flowing from a universal energy source flowing into your body and out your hands. When you are done with the psi ball, either dissipate the energy into the earth (grounding), or use the energy for other purposes as needed.