This is a shiny hunting method that involves breeding two Pokémon of differing country origins. This increases your chance of hatching a shiny Pokémon.
This method is more difficult. Using the item Pokéradar in a patch of grass, you have to keep encountering the same species of Pokémon every time. The first time you use the Pokéradar, you will see some squares of grass in the patch shake. Just walk into one(you will need to use repels so that you don't encounter a random Pokémon on the way). Be careful which one you walk into though, try not to pick ones on the edge of a patch. After you defeat the Pokémon from this first patch, you will see more grass shake. Judge which looks like it shook the most and go to that one. Keep repeating this. Once you get to a chain of forty, your chance to encounter a shiny is increased. Once you get to forty, just keep resetting the Pokéradar until you see a sparkly patch shake. This patch contains a shiny.
This method is similar to Pokéradar chaining, but easier. Unfortunately you are limited to aquatic Pokémon. All you have to do is consecutively reel in a Pokémon using a rod. This can be done by having a Pokémon with the ability Suction Cups at the front of your party. The Pokémon you encounter don't have to be the same, and you can just run away from them. Just don't move from the spot once you start your chain.
Those are all the methods I know, it is also said that your chances are increased in the friend safari. You can also increase the chances further with the Shiny Charm, which can be obtained from Professor Sycamore after you complete the National PokéDex.
Source: Knowledge and experience
Hope I helped!