Only a part of human brain stays awake - the part in charge of understanding the hypnotist's speech.
Maybe not precisely understanding, but receiving vocal orders directed to subconsciousness, which pass by the control of reason (that is why some people, for example, bark if the hypnotist tells them to).
Hypnosis has several stages...
the depth of the hypnosis determines which orders will a hypnotized person comply and how influence will they have.
In the initial stages the patient will not as easily bark (he'll probably wake up).
In a deeper stage he'll bark repeatedly, but still, if he is suggested to, for example, kill, he will not do it (unless we are talking about a criminal with no moral what so ever).
Hypnotizing a person is much easier than what is considered to be.
We often hypnotize ourselves without even realizing it (for example, if we stare at something and have no idea what we're thinking about).
When we want to hypnotize someone, we usually do it by exhausting his senses, physically (we tell him to stare at a moving object) or by suggestions ("you are very tired, your eyes are closing, you are now asleep...
That way the patient slowly starts listening to a hypnotist's voice only, paying attention to nothing else.
The depth or the hypnosis is determined by duration of those suggestions, by how convincing the hypnotist is and by the nature of the patient himself.
Now I'll describe one of many methods of hypnotising a person more thoroughly: In the beginning, the most important thing is an entering conversation with the patient, in which the hypnotist thoroughly describes the entire process.
It is very important to detail explain all the phases to eliminate the patient's fear - the greatest obstacle to a successful hypnosis.
Here I have to mention a very important fact that nobody can be hypnotized without a consent (hypnosis during which the patient is asleep is a special case, because the patient doesn't know what is happening).
Consent is not enough - it is necessary that the patient really wants to be hypnotized and has a total trust in the hypnotist.
In case that any of these terms are not fulfilled, the hypnosis is not possible.
There are people who don't comply with suggestions, or simply don't have enough trust in the hypnotist to allow a free access to their minds.
Those people are very difficult or even impossible to hypnotize.
However, in most cases, hypnosis is possible - by simplest methods.
The goal of the next phase is to exhaust the patient's mind and slowly start putting him asleep by physical methods.
There is a huge amount of those methods, and almost every hypnotist evolves his own.
Among all of them, the most known (but not the most efficient one) is moving a finger, a watch or some other object in front of the patient's eyes.
In my opinion, the most efficient one is when the hypnotist takes the patient for his shoulders and starts moving him backwards around, for example, a table, during which the patient has his eyes closed.
It makes a person sleepy surprisingly fast, and everything is ready for the next phase.
In the next phase the hypnotist puts a patient in a comfortable position and then suggests how tired he is, how all his body parts are very heavy, how he feels the need to sleep...
This lasts for about 10 minutes, or until it's noticeable that all of the patient's muscles are relaxed and that he is slowly starting to sleep, completely allowing the hypnotists voice to guide him.
In that moment the hypnotist mentions that the patient's sleep slowly becomes hypnosis, and that he hears nothing but his voice which guides him.
The patient is now in the state of hypnosis.
How deep that state is depends on the strength of suggestions, and the expressiveness of the previous phases.
Hypnosis can be deepened simply suggesting that the patient is going deeper and deeper in the hypnotic state.
During hypnosis the hypnotist gives certain suggestions to the patient (to quit smoking for example).
The last phase is waking up the patient.
Before that it is very important to suggest that the patient is rested and that he feels great and energetic.
After that the hypnotist suggests that, for example, after counting to 10, the patient will wake up relaxed and (if wanted) he will not remember the entire process.
If that, for any reason, doesn't work, it's useful to apply some other methods, like clapping hands or snapping fingers - that will surely work.
If you don't like the idea of someone "talking" to your sub consciousness (in spite of me convincing you of its harmlessness), but you want to use many advantages of the hypnosis, the solution is self hypnosis induction.
Standard method for self hypnosis induction is to use mp3 tapes with hypnosis suggestions, there are lot of specialized tapes for e.
weight loss or stop smoking etc.
But this way of hypnosis is not really effective because mp3 tape doesn't know when you really are hypnotized and when it should start with suggestions - it depends from person to person (suggestibility, concentration, power of visualization etc.
I am working on biofeedback self hypnosis - the hypnosis method where you using taped instructions, but you are also connected with computer which measures you brain wave frequency and indicates your state of mind.
Computer controls taped instructions and gives you just the instruction you need at the specific moment.
I believe that this approach will make revolution in self hypnosis area.