Choose visible details
Write about the surface, shoreline and surrounding space without turning them into claims about fish or depth. Keep the description concrete. You do not need to account for every part of the scene. One clearly described detail can be enough for a useful entry.
Keep the time honest
Record the date and duration if known. Mark approximate information as approximate. A photograph’s colour is not a weather measurement. Do not reconstruct precise conditions after a week simply to make the notebook appear complete.
Read entries together
Compare two notes and ask what actually changed in the observations. Leave explanations separate. A notebook can help you notice patterns to investigate, but a small number of outings does not prove a cause or a dependable result.