Inhibitory actions are one of the two basic types of magical actions a person can use to induce an altered state of mind, and in that state of mind do a magical working. Inhibitory actions involve inhibiting sensory information in order to force the magician's attention inward. The benefit of doing this is that it removes sensory distractions from the magician. At the same time it should be noted that there's no such thing as true sensory deprivation. The magician is always experiencing some kind of sensory information. Below are some examples of inhibitory actions: Meditation: The goal of meditation is to focus the attention of the person. While some will argue that successful meditation is being able to empty your mind, I'd argue that empty mind is just one form of meditation. Taoist Water Breathing Meditation doesn't focus on emptying the mind, but instead focuses on dissolving emotional, mental, and physical tension in the body in order to help the person circulate his/her internal energy or Chi. In fact, from my own studies, the majority of meditation techniques are less concerned with emptying the mind and more concerned with teaching a person how to harness his/her internal energy.
All the same, meditation does involve learning how to tune out or ignore sensory information and distractions occurring around you. A good meditator is someone who can meditate in diverse environments with different levels of noises and other such information without being disturbed by it. S/he will hear the noises, or see the people, but not acknowledge them, because s/he is able to ignore it as extraneous information.
Meditation can be useful for achieving an altered state of mind. Moving meditation, which I'll discuss in excitatory actions, is useful for magical work focused on the world around you, while breathing meditation is useful for doing internal health work (physical and emotional), and/or focusing your mind on a virtual or astral environment where you are working your magic.
A good best practice for meditation is to focus on your breathing. When you inhale, breathe in with your diaphragm. There are different types of breathing, but with each type it's still important to breathe into your diaphragm. This allows you to use the full capacity of your lungs and greatly aides in inducing an altered state of mind. Focusing on your breath can also teach you to be aware of your body and the way your internal energy flows. Because breath is a cycle it allows you to tap into the cycle of your internal energy and its circulation. Breath is the rhythm of your internal energy.
Sensory Deprivation: Sensory deprivation involves depriving yourself of one or more senses in order to focus your mind. There are multiple methods and tools of sensory deprivation. For example a sensory deprivation tank is a tool that a person can use to achieve an altered state of mind. The person is put into a tank of warm salted water, with no light. S/he will float in the water and lose sense of his/her body and in the process achieve an altered state. A bath with salted water can also be used. Turn out the lights and get the blinds shut and you can create something of an environment that's ideal for sensory deprivation.
Another method for sensory deprivation involves some kind of bondage or restraint. Putting an eye cover over your eyes, ear plugs in your ears, or having your wrists and ankles bound to restrict can induce a state of sensory deprivation that you can use to create an altered state of mind. When you find that you can't move or that one or more of your senses is somehow restrained it tends to sharpen the other senses, but it also sharpens the mind, which can then be directed. It's important to be careful with bondage. Make sure the skin has enough room to breathe and if your limbs start to get numb, it's time to get out of the restraints.
Dream Work: When you go to sleep you are shutting down your awareness of your body. Your dreams are a way for the mind to process information received during the day, but they are also much more than that. If you can enter into lucid dreams, you can use them to do internal work and for other magical activities. I'll admit, I'm not impressed with Western techniques for dream work, mainly because they mostly focus on keeping a dream journal. I have found The Tibetan Yogas of Dream and Sleep by Tenzin Wangyal Rinpoche to be helpful, partially because he provides specific exercises to do to help you induce a successful lucid dream state.
Inhibitory activities typically take more discipline and dedicated time to learn than excitatory activities. The benefit however is that over time a person is able to enter into very deep altered states of mind and can apply the discipline to all magical activities (and for that matter to life in general). Because the focus is learning to quiet and focus the mind and senses, the magician ideally is using some type of inhibitory activity as part of their daily work.
What else would you include about inhibitory actions? Are there any types I've left out?