An "alpha state of mind" is what scientists associate with "right brain" activity, or our subjective senses of imagination, creativity, memory, and intuition.
When you are actively awake, you are typically in a state of mind known as Beta, with brain wave activity between 14 and 30 HZ.
When your brain wave activity slows down to between 7 and 14 HZ, you are said to be in an alpha state. It is considered a "relaxed" state of mind that allows you to be more receptive, open, creative, and less critical. Edison, Einstein, and many other brilliant thinkers considered a daily ritual of accessing an alpha state of mind essential to their work.
When we utilize the alpha state, we have better memory and recall. And because we are calmer, we tend to be more focused and make better decisions.
We access this state quite naturally during sleep, when day-dreaming, or more consciously with Meditation and Self Hypnosis. In fact, many times throughout the day, your brain will dip into an alpha state, even when you are awake with your eyes open.
Learning to access an alpha state at will, can help you with memory, creativity, and intuition and if used on a regular basis --even for short periods-- you will be able to cope with stress more easily and your anxiety will decrease.
In my experience as both a practitioner and a teacher for over twenty years, the Silva Meditation Techniques offer the easiest, most efficient way to quickly and reliably attain the alpha state.
To get into an alpha state you can also use any induction for self hypnosis, or any entry method for meditation. Or you can simply close your eyes and count backward from 100 to 1, telling yourself you are going deeper. All forms of self-induced state change typically require some form of auto-hypnosis or auto-suggestion. Meaning simply that we take conscious control of our state of mind and by using affirmation or mind visualization, we can create the change internally.
Of course you can also enter this relaxed focused state by listening to a guided meditation or even relaxing music. In my article Mind Relaxation by Mozart, I discuss how different types of music have been proven to affect people in different ways.
Accessing an alpha state of mind is particularly useful for studying or test taking. Before each study period relax yourself mentally and physically for a few minutes and say to yourself that in a few moments I am going to open my eyes and read a lesson on _____. Give it a subject and title -- as if you are creating a space for that lesson in your brain. Tell yourself that you will have excellent memory, concentration, focus, and understanding. Then open your eyes and read your lesson. When you are finished, get back into your relaxed zone and recall the main points that you just read. Tell yourself that you will be able to recall the information anytime in the future. Students also find that using self-hypnosis anchors help greatly with recall during tests.