Answer:
The ONLY way to get one is to just fight as many wild pokes as you can. Your chances are 1/8192, so the more you battle wild Pokemon, the better your chances. Nothing in the game has an effect on getting a shiny encounter other than luck, don't waste your time.
i found one in 2 hrs it was a green tangela i was whaching people on youtube get it and only took 2 hrs
hear are some steps that may help.
1 pick a Pokemon u want to be shiny
2 find the grass its in keep looking
3 the more u run into it the bedder chacnce of finding it!
4 maybe looking up on youtube where the person found it maybe useful