Even though the number of vegetarians and vegans is increasing every day, it's hard to find a vegetarian or a vegan friendly restaurant, if you are visiting a new city.
Before visiting a new city, I always make it a point to visit the wonderful website Happy Cow.
Happy cow lists all the vegetarian and vegan restaurants when you enter the zip code of the place you are visiting. Happy Cow also lists all the health food stores, vegan-friendly and vegetarian-friendly restaurants.
So even if you're not a vegan or a vegetarian, visit Happy Cow - amazing website to find good food.