Instructions
Explore the world of your Pokémon title, and fight as many Pokémon as you can possibly find. If you fight enough, you eventually will encounter a shiny Pokémon.
Trade with another player that already has captured the shiny Pokémon you like. This probably is the easiest method of obtaining one.
Look for swarms of certain types of Pokémon. Your Other Rival's sister can alert you to which Pokémon are swarming and where they have been seen ---- the more Pokémon you encounter of the same type, the higher your chances of encountering a shiny.
Breed two Pokémon from different international versions of the game. For example, a Rattata from a U.S. version of "Pokémon Black" bred with a Vulpix from a Japanese version will have a higher chance of creating a shiny Pokémon.