The connections between your brain's neurons, called synapses, are important in maintaining cognitive ability, according to Massachusetts General Hospital's "Mind, Mood, and Memory." Protect your synapses by reducing stress, stimulating your brain with new experiences, exercising, challenging your mind and behaving healthily--especially avoiding too much alcohol.
In his book "Your Memory: How it Works and How to Improve It," Dr. Kenneth L. Higbee, professor of psychology at Brigham Young University, suggests several beginning strategies for improving retention. The first is repetition. But instead of repeating the information you wish to retain several times over an hour or so, repeat it a few times every day over an extended time--at least two weeks.
You can also use visualization. Imagine the information--not in the form of words, but what the words represent. Also, sharpen your focus. Relax so you can devote all your attention to the information.
Finally, be aware of context. Rather than learning something you will need for an exam when you are at the beach, for example, learn it in an environment similar to the classroom.
You can also make the information meaningful. One way to do this is to increase your familiarity with it by spending time learning about similar things. This will not only increase your exposure to the information, but it will also make it more meaningful by putting it into context. You can also associate the information with things you already know, like associating the map outline of Italy with a boot. Next, organize the information into patterns or, if possible, rhymes. You can also organize the information into categories or chunks. Higbee cites a study in which people asked to organize material remembered it as well as those instructed to learn it.