What does it take to become a Featured Background Artist?

I can't quite put my finger on why I was always picked as someone who was in the scene with the actors instead of being "atmosphere", but I believe it was because I was professional at all times. My wardrobe was always on point, I wasn't a goof-off, and the most important thing was...I made relationships with the Production Assistants on the set. Remember, it's who you know in Hollywood.