Establish a connection to the energy of the earth. Grounding helps to prevent the body from becoming overly stressed. It helps to keep your energy system safe when you are doing spiritual work or magik. It can rid the body of excess energy at the end of a spell or ritual, and prevents you from feeling agitated or over tired after a magickal working. Grounding may be done before or after a ritual, or both.
A simple way to ground is just to sit with your palms on the earth. Feel the energy flow from the earth into your body from your palms. The energy flows up your arms, into your body. Feel the energy circulate through your body and back to the earth through your palms. Visualize the energy moving into the earth. Feel all the excess energy you may be carrying flow into the earth.
If you are in a home, sit on the floor and feel the energy go down past the foundations of the house and enter the earth.
The eating of fruits and vegetables after grounding should help also, and can never hurt.