no matter what you do, finding a shiny pokemon is always gonna be rare, and down to pure luck. the only ways to get them are either through being lucky and finding one in the wild, or by soft resetting.
the only 2 methods i know of that raise the chances of getting one are a method ive heard of that involves breeding pokemon from different countries (say, if you get a japanese ditto off the GTS). using this method, i think the chance is reduced to about 1 in ever 2000 pokes.
the only other method that gives a better chance of getting a shiny is getting a copy of diamond/pearl/platinum, and learning how to chain!