1. Dianne has her own style and rarely follows current fashion. If you saw her on the street, she would stand out in a crowd.
2. Paul does what everyone else does and goes along with what other people think and say. He doesn’t like to stand out in the crowd.

Compare to: stick out like a sore thumb. Whereas stand out in a crowd is usually a positive attribute, stick out like a sore thumb is a negative one. The expression stand out in a crowd suggests a degree of distinctiveness and independence.