There are many theories as to how to make memorizing easier. You can employ a memory expert, such as myself, to help you with the basics; you can buy cd’s with memory lessons; and you can take classes in speed reading and other memory techniques. They are all excellent ideas that can benefit you immensely, but in the end it is entirely up to YOU to find the best way to learn to retain information.
Memorizing skills are an art, acquired with training, practice, focus and the desire to improve your ability to remember and recall the information you want to keep. Usually the art of memorization is referred to as mnemonics – methods of remembering information that normally would be difficult to recall. Basically, the principle of mnemonics is to use as many different parts of your brain as possible to set up a code to process the information. 
The style the person learns through has an affect on the sort of mnemonics that can be considered. Visual learners (approximately 65% of the population) are more receptive to mnemonics, but auditory learners are able to adjust to their learning styles by substituting auditory cues in place of visual. Kinesthetic learners can use their imagination to perform plays or actions, as well as use memory tools to base their memory techniques. Keep in mind that most people utilize more than just one learning style all the time.
Our brains interpret complex stimuli (such as colors, structures, language, emotions) through the senses (sight, smell, taste, touch and hearing). We create a picture in our minds of the world around us through this stimuli and our memories store all of this very efficiently. Much of what we remember is presented in such a way our brain has to “decode†it, making remembering it more difficult. An example would be a handwritten letter.
Points that make things easier to remember, no matter what learning style you use:
§        Make the images you create in your mind pleasant and positive ones.
§        Inject humor as often as possible. We remember more with humor.
§        Take notes and write things down you want to remember
§        Make the images vivid and colorful
§        Understand the material before you try to remember it. If you don’t understand it you won’t remember it.
§        Teach it to someone else. If you can do that you understand it, and it will solidify it in your mind
§        Try creating a simple formula that will make it easier to remember
§        Relate what you want to remember to your own experiences
§        Break things down into smaller segments instead of trying to remember everything at once
I hope this has been some help in showing you different ideas that can help you improve your memory. This is Ron White, two-time USA Memory Champion , memory training expert, and memory keynote speaker.
Sources:
Strategies for Success – Study Skills Memory Techniques: http://www.alamo.edu/sac/history/Keller/accditg/ssmt.htm
Mind Tools – Memory Improvement Techniques: http://www.mindtools.com/memory.html