A notebook can be useful without becoming a project. Leave the first page unremarkable. Write the date, the place where you are sitting, and one detail you would otherwise forget. A faint reflection on a wall is enough. So is the sound of a door closing down the street.
Try a small structure: one colour, one sound, one texture, one change, and one question. Keep each answer to a line. The limits help you choose details instead of trying to preserve an entire day. They also make the practice possible on mornings when you have very little time.
Write down what you saw before deciding what it means.
Be concrete. Instead of writing that the light was beautiful, describe the narrow amber stripe along the edge of a glass. Instead of recording a busy street, notice the pause between two passing buses. Exact words make ordinary observations easier to return to.
A rough sketch belongs here too. Draw the outline of a shadow or the arrangement of three objects on a table. The drawing does not need to resemble a finished picture. Its job is to slow your attention long enough to see a relationship you might otherwise miss.
At the end of a week, read the pages without grading them. Look for something that returned: a colour, a place, an hour of the day. These repetitions can become the beginning of a small collection. Keep the notebook close, and let the next page stay simple.