A small record of seasonal changes
Pick one tree, courtyard or stretch of pavement that you pass regularly. The place does not need to be picturesque. Returning to the same view helps separate a lasting change from the passing impression of a single day.
Record a few concrete details: the first fallen leaves, a different bird sound, the length of a shadow at lunchtime. Use the same approximate time when it is convenient, but do not let a missed day become a reason to abandon the record.
After several weeks, arrange a few notes together. Patterns often become visible only in retrospect. Keep room for uncertainty; a personal field record is a collection of observations, not a complete explanation of a place.