For this you engage in activities or mind exercises that stimulate your brain. Some points to ponder about brain power. Thinking is brain exercise. Brain imaging on humans show immediate changes in blood flow whenever our mind is stimulated. This stimulation increases the density of the all important dendrites.
Education also affects brain development.
Pursuing educational avenues increases cognitive ability, measured by memory, concentration, language, visuospatial ability and orientation to time and place. A more informal and lifelong approach to learning is just as important to rouse your brain. A repertoire of hobbies learned in our youth gives us interests to keep our minds occupied as we age. Taking an active interest in new activities will stimulate your brain It is also important not to put your brain into overdrive and keep it in high gear. Neurosynapses do not operate as well under chronic stress.