Regarding memory improvement, the book recommended doing the following. this technique is similar to the one on which AlexK commented.
Pretend you have a pencil attached to the end of your nose. Find something (picture, math forumula) and trace it with your "nose pencil." Your eyes should trace the details as well. Your attention should focus on each detail as you trace it. Don't try to look at everything at once. Focus as small as you can without straining. Then close your eyes, and re-trace the object with your eyes closed. It is important to move your head while doing this, both with the eyes opened and closed. As you can see, this "exercise" is simply a demonstation of the two principles (movement and centralization) that I mentioned earlier. Those nose pencil is only to make sure you are moving your head.
