What I think is typical is that although I did indeed tear out the clippings I liked, I didn't go on to do anything with them, apart from throw them away at the end of the year, untouched and unread. Which sort of sums up how I feel about myself - other people think I'm organised, but I know I'm not.
I was inspired to write about defining moments when a friend told me a funny story about their performance in the school Nativity play when they were about 6 or 7. It was so funny and charming and character revealing that I immediately asked permission to 'give' the anecdote to one of my characters in the current book. I don't know yet if I'm going to use it, but that character is now clearer to me than before.
It's an interesting way of honing down the essence of a character. Is there an incident that defines them? You could either show it happening now or, if it's in the past, have them or another character describe the incident, the more specific the detail, the better. Use that incident to show their character.
Stuck for ideas? Think of some defining moments of your own and what they say about your personality and use them as a basis for the fictional characters to remember.