Grounding vs Centering

Before we do spell work, meditate, or any other spiritual work like divination, we usually take a minute to ground and center ourselves. This is taught in practically any craft or spiritual book you will find on the market. Many times the author will assume that you know/understand what this means, and will often give their take on easy ways to accomplish this. These two concepts are either used together or interchangeably as well. They are actually two different practices and can be used together or separately. There are different ways to do both as well.
Grounding, usually done first when it is necessary, involves connecting oneself to the earth and its energies to clear out any excess or negative energies one may be harboring so they can be cleansed and recycled through the earth, and then bringing the grounding earth energy into oneself. Earth energy is stabilizing and helps you become more aware of and connected to your surroundings, as well as the present moment. A few ways in which you can do this is by visualization (usually yourself as a tree with your energetic roots reaching through the earth to the center and connecting yourself to it), earthing (walking barefoot in the grass opening yourself to the connection with earth), sitting in nature (on the grass/a rock, by or in a stream, against a tree, etc..) and opening yourself to your surroundings/practicing mindfulness, meditating with a crystal like obsidian or smokey quartz, or by listening to a guided meditation. These are just a few ways. You can use whatever technique works for you in each situation.
Centering is about balancing your energy and bringing it into alignment. Rather than connecting with outside energies like you do when grounding, you are connecting with the energy of self this time.  Not only does this help bring about an inner peace, it offers you the chance of self-reflection, making sure the energies you have held on to during grounding are both calming/peaceful, and your own (something empaths should be checking regularly, especially after social situations). This can also be done through visualization, guided meditation, breath work (alternate nostril breathing techniques are good for this), or dance/movement (which can make you more aware of your body and how it is feeling, as long as you are present mindful about it).
Both of these techniques are beneficial, and necessary to keep you balanced, help you manage stress, and work with/manage the energies used when performing any kind of spell or spiritual work. What is your favourite technique to use? Do you practice these before or after your work, or both? Have you heard of/used any unique techniques for either, would you share them if you have?