I moved back to NYC in 1994 after a 23 year absence (in California).
When I came back, it was to mayor Dinkins' New York City. Rudy Giuliani was inaugurated January 1, 1994, so I got to see the transformation first hand.
It was astonishing. Giuliani operated under the "broken windows" theory of crime. Addressing the littlest of crimes deters the big crimes. He quickly achieved a dramatic cut in murder rate. Then, quality-of-life crimes and squeegee guy problems--gone! He instituted community policing, a fancy way of saying putting cops on the street – not in patrol cars.
He spearheaded the transformation of Times Square from sleezy porn shops to a world-class family friendly tourist destination.
The republican Giuliani won in an overwhelming democrat city by promising 2-3 things. He kept it simple and he kept repeating those two or three things. That's why I say Giuliani and Trump are similar. Trump has three core principles he is hammering: immigration, national security, and jobs. Ronald Ragan also kept it simple when he campaigned. A simple, clear, easy to understand message always wins out.