There are various websites where you can register for Lumosity and try out different memory games. You can even choose which one you want to play by choosing one of the options that are given to you. For instance, if you just want to memorize a word or a short phrase, you just have to type the information into the text box prompt and wait for the word or phrase to appear on the screen. If you want to memorize an entire lesson or an entire book, then you have to learn how to control your brain's activity so that you can focus and absorb the information better.
Another good feature of Lumosity is that you can set your own personal time limit for how long you want to practice concentration and speed learning. This means that you can set a number of minutes per day that you want to be focused on your memory improvement exercise. Since the online memory games are designed to be fun, you can always find something that will stimulate your mind. After you've spent few minutes practicing your concentration skills, then you'll be surprised at how easily you can get an excellent grasp over your short term memory and even improve your short term and long term memory.