Reading. It is well known that reading increases mental activity. Read for the enhancement of daily life. Even reading a small amount, 15 mins or so, will lead to an increase in mental capability. As reading becomes a habit, it will be easier to digest larger portions of books. Learning in this way is key to unlocking the mind.
Art. Art is a human invention. It is an expression of the intangible spirit inside human beings. Children are always experimenting with art. They pretend and express themselves fully through artistic forms. Their minds are constantly expanding in part because of this creativity. Keep your mind expanding by finding an artistic outlet like learning a musical instrument, painting, acting, sculpting, writing etc. Find the right outlet and release.
Meditation. Meditation is renowned for expanding the experience of consciousness. It requires dedication and practice, but the benefits are impossible to measure. As mediation becomes a habit, the realization that this world is a product of the mind and thus malleable will be apparent. This is perhaps the most difficult and beneficial of all mental practices.
Exercise. Not only is exercise good for the body, but it is also essential to a healthy mind. The increase in blood flow and good hormones has a huge effect on brain chemistry. Furthermore, the difficulty of exercise will reveal, consciously or otherwise, that the only limits are the ones applied by your own mind. Break free from the mental by engaging the physical.