The first thing to say is that everyone can become psychic. Psychic ability is innate in all of us and those of us who aren't aware of it need to learn to tap into that ability.
There are a number of ways of training to become a medium.
The College of Psychic Studies was founded in 1884 in London. They offer lectures and training courses for those interested in developing their psychic abilities, covering psychic healing, spiritual development, counselling etc. It is also possible to have consultations with sensitives, or psychics.
It was founded by people interested in psychical research and proving the existence of life after death.
You could find a local psychic in your area who is prepared to help you become a psychic. Joining a psychic group, or visiting your local Spiritualist church can help you find a mentor, or tutor. There are online courses and workshops. Joining a free chat room could be a good way of seeing what sorts of courses are available and what people recommend. Psychics may be able to give you tips on how to develop your psychic abilities at home.
You can purchase self-books on psychic development. These usually cover the different types of psychic abilities, such as clairvoyance and telepathy, and give exercises you can do at home to relearn how to use psi (psychic abilities or psychic phenomena).
To start working as a psychic is very easy. There are no qualifications you have to have, or recognised organisation you have to be affiliated to, so when you are ready to start working as a psychic you just need to advertise your services. If training as a medium, you can work through Spiritualist churches. Psychic fairs can be a good place to become known as a psychic. Psychic healers or psychic counsellors can work from home. You just need to put an advert in the local paper or new age shop.
Psychic readers give people intuition-based readings using tarot cards, or tea leaves, or advise people with the help of their spirit guides. Another popular method is palm reading. Some psychic readers give readings over the phone for big companies which charge the caller per minute.