I love NY, it has a certain 'energy' that makes you feel alive. People I asked on the street for directions were very willing to help. I walked as much as I could, but it was also easy to use the subway when I needed to. The great view from Empire State Building helped me a lot in my orientation. I learned there about the 5 boroughs of NY (Brooklyn, Queens, Staten Island, Bronx and Manhattan) and spotted most of the city top attractions which are in Manhattan. I walked peacefully in Central Park and my dream come true when I got to Strawberry Fields (tribute to John Lennon)
There are a lot of things you can do, it depends on you to make your visit great. Try to choose what YOU would love to see (not just because they are popular).
There are so many things you can do for free like walking in Time Square or walking across the Brooklyn Bridge, visiting Grand Central Station, Saint Patrick's Cathedral, or you can take a ride on the Staten Island ferry to see the Statue of Liberty. Peace