I like it when I encounter shinies on pure luck. It just excites me, haha. My second favorite would be chain-fishing. I've tried it before, and was pretty successful. With this method, I was able to encounter shiny Tentacool and Goldeen. Couldn't catch the former though, as I accidentally made it faint. PokéRader chaining is my least favorite, because, for me, it's just way too complicated. I've done it plenty of times before in Platinum, but couldn't run into any shinies at all.