For instance, I recently needed a line, just one line, for a query letter that best described what my main characters were feeling. It is their "A-ha" moment. I was struggling with it until I saw someone run through a park during a festival. The girl was with one friend, left that friend, ran back to someone who called to her and began to talk to them. She waved the first friend away, but the girl stayed put and waited on the friend who had left her to return. That simple act was what I needed to see. My character had left his wife to fight in a war, came home broken inside and was distant, even abusive. To the wife's credit, she didn't run away, even though her husband was basically waving her away. She waited for him to want to return to her.
Presto! Problem solved.
I also went to a concert to see some friends perform. Since I've seen them several times, I know their set list about as well as they do. I know they saw me in the audience (we made eye contact and smiled), and so they may have noticed that I did not pay strict attention to them during their show. I was looking to the right and left, making mental notes about the physical appearances of men, women and children in the audience. How they walked, talked, and reacted to certain songs and comments. Describing these traits will come in handy later in future stories. In fact, I wore a T-shirt that read: "Be careful or you will end up in my novel". After the concert, while talking to my friends, they laughed at the shirt and said they were going to make up shirts that read: "Be careful or you will end up in my song".
So watch out. You've been warned.