I used to be a heels person. I would wear heels everywhere to the point where when I would wear flats my calves would hurt. Little by little I started wearing flats and sneakers and now I hardly wear heels. I finally learned they are not conducive to taking advantage of NYC.
Not wearing heels everyday even got me to get a Citibike subscription last year. At first I was pretty nervous about riding (especially since I ride without a helmut) but soon enough I was riding a couple of times a week. When my friend invited me to the Frying Pan (it happens to be on a pier on 12th Avenue, not close to any subway) instead of groaning I was delighted because I could ride the bike.
I use the google map app to find my route because it has a biking option which highlights the bike lanes. If you are riding without a helmet you should seek the bike lanes.
I also use the Citibike app because it shows you where to find the docking stations. Sometimes when you get to a station there are no bikes or its full. The app helps you find another without wandering around. It always lets you know how many bikes/docks are available.
I noticed there are a lot more people riding. I like it because now I go to the park all the time. Sometimes I even wake up early and go before work! My favorite these days is the Normal A Rockefeller Park in Battery Park City I can get there in under 12 minutes (i'm a leisurely rider, taking in the sites and seeing what is new in the neighborhood). Walking there takes about 30 minutes.
Photos made possible by Citibike ride: