Hypnotists are encouraged to have a unique view of the unconscious mind. It is suggested that the unconscious mind holds all experience that isn’t consciously available. This also means that the attempt to improve your memory becomes an attempt to enhance your ability to recall. This is stimulated by research showing that electrical stimulation of the brain can make a person remember something they had forgotten, right until the electrical stimulation stops, then the memory is gone again.
You may also have seen television shows about “savants” who are persons with exceptional mental abilities (made famous by Dustin Hoffman in the film Rain Man). These people seem to remember everything at the expense of social skills. It’s a common belief in hypnotherapy that everyone has a subconscious mind that contains every experience of our life, and that is very capable of performing tasks that are way too complex for the conscious mind.
I don’t believe that memory is a constant that you cannot affect throughout your life. It depends significantly on what you want to remember and your mental strategies. A hypnotist or an NLP practitioner can help you develop strategies for the things you would like to recall. Keep in mind that you should have a purpose, something you would like to accomplish by increasing your ability to identify. There is no point in training your memory to have a better memory. When you know what you would like to remember better, you can seek out someone to help you increase your ability to recall.