The old adage a picture is worth a thousand words certainly holds true when trying to organize your notes for studying.
Concept mapping is a technique for representing knowledge in graphs.
The map is built on a hierarchical basis, building detail as you move from the centre. The technique is particularly well suited to taking notes from a text. For example, if you are studying a chapter, the chapter title would go in the centre. The position of an item on the hierarchy was determined by the size and boldness of the font. The pink items where selected from the chapter table of contents.