If your drawing skills are not up to drawing directly onto the page, you got to know that NoteBook has now some tools for shapes, lines and stickies. So for instance if we go to this shape menu to select a rectangle to create a diagram. Select the rectangle,drag it onto the page and we can then rescale. We can also go to the Inspector and then the shape inspector. We got full control over the style, the stroke of the particular object. You can also select shapes from the main menu. You can select a diamond. We scale it. If we wanted to words in the center, we just double click in the center. Then there are also options for lines. There are different types of lines which are configurable through the Inspector. One of my favorite additions are sticky notes. Directly from the toolbar or we can go to the notes option in the main menu bar. I can select a shape circle or can double check in the middle and edit that. I can even put in some hand written text. Another option is a sticky flag. I can move that anywhere on the page. I can annotate it and double click it. And finally we have a reminder flag. I can move that and move it and stick at the edge of the page.
Circus Ponies NoteBook 3.0 - Diagramming & Sticky Notes