In practice
A notebook that leaves room for looking
The best notebook is one that helps you return to an observation.
Begin with a small frame
Write the place, the time of day and one thing that caught your attention. You do not need to describe everything. A shape, a sound or a change in the light is enough to start a page.
Separate what you saw from what you think
An observation can be simple: a leaf has a pale edge, or a bird returned to the same branch. An explanation is a different kind of note. Keeping the two apart makes it easier to revisit a question without losing the original detail.
Leave something unfinished
A blank space can be useful. Come back to the same spot and add a second note. The page becomes a record of attention rather than a finished account written all at once.