What is Grounding?
"Grounding" is a common term in the subject of magick, but also amongst electricians. An electrician "grounds" the electricity from a building (like a house) by planting a large copper stake into the earth which is physically connected to the building. This way, in the case of any electrical problems, the electricity will be naturally driven back into the earth rather than into the home. Although you don't need to plant a metal spike nearby, you still need to "ground" the excess energy that gets accumulated in your body, from magick, energy-work, and life in general.
One of the magicians I learned from mentions that the side effects of not grounding oneself can be to blame for "paranormal" happenings around the person. This is because it's their aura that is "arcing" with the person's surroundings. Arcing is when electricity jumps from one overloaded circuit to another. In the case of our natural energy, light bulbs will flicker and in some cases go out, as I have experienced myself, electronic devices may become faulty or malfunction. Consider everything around you which produces an electromagnetic field; phones, computers, Wi-Fi modems, and anything connected via Wi-Fi, Bluetooth devices, remote controls etc. all of these invisible fields interact with our auras energy.
How To Ground Yourself
The good news is that this is easy and can be done as needed, and it doesn't have to me something "witchy", it can be something like standing barefoot on grass, or the sand at the beach if that's your part of the world, or just on the muddy bank of a quiet lake or a peaceful river that you like to visit. Consider that in Reiki, practitioners are taught to wash their hands with cold water after working with the energy of another to "ground" that energy. So why not try to go for a swim or take a cool shower? Crystals, as they are symbolic and literal fragments of the earth, are also good at absorbing and grounding energy.
It's that easy, but it doesn't mean you shouldn't put your intent behind it when you do it. Washing your hands with the intent of grounding your energy, and adding extra layers of your energy with focused visualization can boost your effects. If you're intently washing your hands, you can focus your attention on how the water feels as it flows down, around, and away from your hands, you can imagine and visualize it taking the excess energy away from you, you can envision the water to be white, you may feel inclined to use a special soap for this, maybe you will create your own and consecrate it, and make it your ritualistic grounding soap.
There are many options as to how one could ground themselves, if you chose to use a crystal you can visualize the energy flowing into the crystal, even if you have no crystals, you can place both hands on a tree, or directly on the grass, and like the other items you can use your mind's eye to project the energy away from yourself and into the earth. Do this for a few minutes or long enough until you feel the effect.