I think, just don't looking for them. Searching make them (seem)rarer. A lot peoples find their shinies when they're EV training (me too).
But if you have enough luck...maybe you can find one easily.
All you have to do is to encounter wild pokemons, if you are lucky enough then you can find a pokemon with a different colour.
And finding a shiny is too rare so dont excpect finding one that fast except if you are lucky.
All you need is a lot of luck. But shinies don't mean anything, they're just there to show off. Otherwise, direct all of your Shiny Pokemon querries here.