The only legit way to get a shiny is to not actively look for them, like my Toucannon and Whismscott, i was training in Poni canon when I ran into cottonee and trumbeak there. people who actively hunt shinies are no better than the injecters in my eyes. Because when they do it, they tend to have the synchronizer pokemon with them and all those other hidden methods to abuse like the masada method, using intimidate and that weird adrenaline item. Just play the game and if you find a shiny, congratulations. If not, keep playing normally and it may happen. I have no respect for people who get their shinies otherwise.