There are many ways to find Pokémon in Pokémon Go, with some more efficient than others.
To understand the best ways, it’s worth remembering the conceit of the game: creatures are found in real-world locations, with the app using Google Maps and Ingress data to place PokeStops, Gyms and other attractions into the game.
It uses different types of areas within the map data to sort where the many different types of Pokémon should be found.