In terms of when grounding and centering comes in the order of ritual, it varies a lot. Some practitioners will ground and center before setting up their altar, some will do it after they’ve set up and before they perform their act of ritual purification (like a ritual bath or smudging), some will perform grounding and centering just before they cast the circle, etc. Depending on the order of your own ritual, how you view grounding and centering, and when you will need energy for your working, you can move it around based on your personal preference.
Centering puts you in touch with your personal power, connecting your mental and spiritual bodies. Centering involves clearing your mind of outside business and focusing upon the task at hand. For rituals and magic to be meaningful and effective, you should not be dwelling on what you had for lunch today or your plans for tomorrow. 'Be Here Now' is a phrase that nicely sums up the idea of centering.
Another important part of centering is your awareness of yourself; becoming aware of the Goddess that lies within us all. This awareness promotes stability, confidence and a healthy ability to express your will.
Psychically, centering allows you to work from a stable foundation, helping to keep you from being magically thrown off balance. The Eastern philosophy of chi is a very good way of explaining the psychic aspect of centering. Our physical bodies have a center of gravity that moves and shifts as we move. Likewise, our energy field has a center that corresponds to our center of gravity.
Male and Female bodies are shaped different and so have different centers of gravity. The center of gravity for a man is usually between the navel and the base of the sternum, whereas the center of gravity for a woman is usually between the navel and the pelvis. Focusing your mind on this area brings your awareness to the center of your energy field. This allows you to use more of the energy you have available, while still drawing energy from Mother Earth. There are several good books on increasing the chi, with exercises that are excellent for working on centering.
Meditating is one of the Thirteen Goals of a Witch. If you've done any meditation before, it may be a bit easier for you to center, because it uses many of the same techniques. Find a place where you can work undisturbed. Try and feel the energy in the Earth and feel it travel up through your core into your body, or you can think like a vacuum and feel it when you've sucked it into yourself. Allow this to fill you up - this can feel like tingling throughout your body.
Once your breathing is regulated, it's time to begin visualizing (picture in your mind) energy. Rub the palms of your hands lightly together, as though you were trying to warm them up and then move them an inch or two apart. You should still feel a charge, a tingling or warm sensation between your palms. That's energy. If you don't feel it at first, don't worry. Just try again. Eventually you'll start to notice that the space between your hands feels different. It's almost as though there's a bit of resistance pulsating there if you gently bring them back together.
Now that you can tell what energy actually feels like, you can start playing with it. This means you can focus on that area of resistance. Close your eyes and feel it. Visualize that tingly area expanding and contracting, like a balloon. Try pulling your hands apart, and stretching that energy field out, as if you were pulling taffy with your fingers. Try visualizing the energy expanding to the point where it surrounds your entire body.
After some practice, you'll even be able to fling it from one hand to the other, as if you were tossing a ball back and forth. Bring it into your body, and draw it inward, shaping a ball of energy inside yourself. It's important to note that this energy is all around us at all times. You're not creating something new, but simply harnessing what's already there.
Make sure these are positive energies! Keep your mind on the idea of bringing calm, positive and happy energy into your body from the Divine. Some people find that it's easier to regulate their breathing if they count, or if they chant a simple phrase, like "Ohm," as they inhale and exhale. A runic or personal mantra would also work if it helps to focus. Other people will also raise their arms to the sky and envision energy coming down into them.
Generally to end this process, one might envision their channels returning into their body. This is important to do, or you may lose energy and this can leave you light-headed or even cause a drain if you aren't careful. Try to do this closing without disconnecting from the Goddess or Earth - it can bring reassurance to be able to feel this presence throughout your day.
Each time you center, you'll repeat this process. Begin by regulating your breathing. Then focus on your energy. Eventually, you should be able to control it completely. The center core of your energy can be wherever it feels most natural for you - for most people, it's ideal to keep their energy centered around the solar plexus, although others find the heart chakra to be the place where they can focus on it best.
It is a good idea to do this before bed and when you wake up. Grounding and centering is also useful before prayer, introspection, meditation, visualization, healing work, energy work, ritual, or any other spiritual or emotional experience in addition to serving as an aid to connect with deity in everyday life, when we feel lost, rushed, scattered or unfocused. Regular practice will help improve your general mood and attitude towards life.
Keep in mind, it may take some practice to get the feel of this; it can be difficult for some to recognize or gain a feel for energy, but try not to be discouraged by this - it takes practice to learn skills. It may be hardest for people who have not practiced meditation before, who are depressed, or have little or weak connection to nature, but that's okay, because the point of this practice is to fix that!
Another note, make sure to thank the Goddess! This can be as simple as thinking kind thoughts toward her and saying 'Blessed Be'. After you've been doing this for a while, it will become second nature. You'll be able to center anywhere, anytime... sitting on a crowded bus or stuck in a boring meeting. By learning to center, you'll develop a foundation for energy work in a number of different magical traditions.
"Centering is a process of finding out who and where you are. It involves increasing your holistic perception—that you are a whole person, not just a collection of parts. Where grounding is a connecting experience, centering is often a soothing one. To center is to locate that part of ourselves where we perceive our true and whole self to reside, the center of our spirit, and to function from and with that center. Life is often reactive; to be centered is to behave based on free will at all times, not in response to stimuli." ~ Deborah Lipp