Grounding is a way of centering yourself. It can be used to calm your mind, body and soul. It is a good way to focus your energy for magical purposes. As well as releasing energies into the earth.
Grounding reconnects your connection to the divine, to become one with the realm. Doing this reaffirms your own divinity and connects you with a source of magical energy greater than anything you could ever generate on your own.
Grounding helps activate all of the energy centers (or chakras) along the spine. Balance between the centers is necessary to prevent illness.
In a group situation grounding can help establish what is known as group mind: that state of mind where all members of the group think and act as one, at least for the duration of ritual, and often after.
Lay flat on the ground with palms of hands flat on it. Allow your energy to seep into the ground.
Eating something starchy.
Another technique is to hold a piece of hematite or an item made out of lead. These substances too, have a natural grounding quality, and will have some effect by themselves. But to get the best effect, hold the object and imagine the excess energy draining into them from all parts of your body. When you are finished, hold the object under a stream of cold water and imagine white light pouring through the stone as the water washes it. This cleanses the stone.
Put a bit of salt on the tip of your tongue, or run the tips your fingers through some salt. This will have a natural grounding effect, eliminating the excess energy.
Visualization can be very important when grounding. You can imagine many things to aid you. A few examples are imagine growing roots, or a white and/or green light pouring out from your body into the ground. Picture yourself full of mud and dirt in front of a lake, walk into it until the water is over your head and walking out clean.