Memory mapping can be a powerful technique for stimulating thinking, and as a memory power boost.
The technique involves drawing associations on a piece of paper. first start with the key idea or word in the center and write close by the sub ideas, then connect these with a line.
This is a powerful memory enhancing technique because it operates on a number of levels at once

Diagramming information coverts the incoming mass of data into concepts and images that are meaningful to you.
It draws on the left-brain verbal, analytical abilities and the right brain spatial, visual abilities, reinforcing facts and data simultaneously in the memory circuits on both sides of the brain.
By jotting down key ideas and indicating connections between them, you personalize the data, arranging them in a way that is meaningful to you.
Because there is always space for further ideas and connections you are prodded to keep looking in new directions.
Since the key elements are all right there on one sheet it’s easier for you to see important connections.
Consciously processing the information– rather than passively listening or reading– makes it more likely you will remember it.

There are some excellent free tools for creating mind maps one of my favorites is freemind