In one blink of your eyes
You have missed seeing.
You must always be observant and store what we have learned during the day for future use.
Hemingway, in his Nick Adams Stories, tells of a young man who was at the front during World War I. The only way he found to keep sane and get to sleep was to recall his entire day. He would start from what happened directly before he lied down and work his way back moment by moment until the time he woke up. He would remember events as fully as he possibly could. Then he would remember specific days in his past also as fully as possible. He did not want to forget even a second of his past in the midst of war.
I have tried this exercise often in my life. It is very difficult to achieve a full recollection at first. After a few weeks, you will train your subconscious to remember everything that happens to you. Events burn in your memory as they happen. This also trains you to pay attention to the events in your life. I still can recall very explicitly ordinary events in my life from many years ago because of this.
Remember, the events that you experience today will help you in the development of a character later in your career.