Grounding is something that I consider to be one of the core practices that is often overlooked. True, many books and beginner study programs include grounding, and suggest it be used after (and sometimes before) rituals. But I feel that the importance of grounding is understated.
I also dislike how there is one generally accepted method used to teach grounding: reaching roots down into the earth and drawing up the energy and letting the excess flow down into the earth. I struggled with grounding for a long time because of this imagery. It's not the connection to the earth, I physically ground a lot when feeling a bit flighty or overwhelmed, I just lay down or touch my hands to the ground (or really sink my feet down solid). It took me years to realize this was my own way of grounding (what can I say...I can be slow on the uptake sometimes).
But it was the inevitable tree/root imagery (and the corresponding sun/spirit light from the sky that is often included in grounding instructions). I'll admit it, I'm not a tree person. I just don't self-identify, and so these types of instructions were very hard for me to follow. What I also disliked about a lot of the basic grounding explanations is that they often don't explain grounding (or centering) much at all. They tell you what you should do, and when you should do it, and sometimes if you are very lucky there will be a little one-liner about how grounding and centering helps to re-balance your energy and rid yourself of excess.
For me, grounding isn't so much about soaking up external energies like a sponge, nor about dumping any energetic sludge that may have been accumulated over the day. It is about opening up, allowing yourself to be as you are meant to be, no more and no less. I think this is why it is a vital practice, not only before and after rituals, but also as a part of your regular life.
Every day, we experience natural fluctuations in our energy. We each have unique flows where sometimes we are high energy and sometimes low. You may be a morning person or a night person, and find you have high energy at those times. Myself, I am not a morning person, so first thing upon waking I am definitely not my best. Unfortunately for me, I am a night person (and right now I don't have the luxury of staying up like I would prefer), so when the time comes for bed I am often still quite buzzed and not tired at all.
Grounding helps me to take control of my personal energy and balance out these highs and lows as I need to. When I am having a hard time getting started, I can open myself up and release that sluggish energy that is keeping me down. When I am overly stimulated, I can let go and relax. Just as our natural rhythms tend to give us energy highs and lows, our energy needs fluctuate as well, so a grounded state might be different at different times based on what you need. By grounding regularly, you will learn to recognize what you need and what is right for you at any given time.
When it comes to rituals, I think that any time we take an active hand in directing our energy (or energy we have called to our purpose), we should take extra care to make sure we are starting from and ending in a balanced position. If we aren't fully grounded when we start, we can find our ritual being led astray by lingering concerns. If we don't ground after we are done, we carry the residual from our ritual which can seriously interfere with our regular activities. This isn't to say that you can never internalize energy from a ritual to use after the physical ritual is done, but it should be done in a mindful manner.
I also think that there tends to be a focus on earth when it comes to grounding. Earth is excellent for grounding out excess tension or nervous energy. It stills the body and is easy to do at any time. But you can also ground yourself in other elements.
Opening to air through breathing or by allowing yourself to be surrounded by wind (great to do during a storm) can be invigorating and cleansing. I find air lends itself very well to singing or spoken release as well.
Water, accessed through bathing, swimming, standing in the rain or even just washing our hands is a great emotional cleanser. No one can see you crying in the rain. If you have ever stood out and gotten completely drenched in a storm, not trying to avoid the rain but embracing it, you find that even weighed down with wet clothes, there is a lightness to you that wasn't there before.
Fire can be a bit harder to approach, and requires more safety consciousness. Flame has always been a comfort to me, I loved lighting a fire in the fireplace as a child or even just lighting candles for dinner. I feel that now, the flame has a presence that extends far beyond it's physical form. Turning off all the lights and burning candles makes the whole room a place of fire for me. I have always been drawn to play with candle flames (being very careful to not burn myself). Fire is where I turn when I need to really go after something aggressively, whether it is a persistent energy that I am finding really hard to let go of or a large project I need to really energize to tackle.
All too often, I think grounding gets overlooked as a minor and simple thing you do after a ritual (sometimes grounding is reduced to a suggestion to eat and drink something, which are also ways to ground, but without intention I feel they fall short, more of a first-aid type of grounding). Like anything, grounding is what you put into it, and if you take the time to make a practice of it, there are many ways to not only approach but benefit from it.