• I hate to say it, but it's all luck. I mean I've played basically at least one game per gen, and I never caught a Shiny Pokemon in Emerald or Soul Silver (Not counting Gyrados..). No matter how many hours you play, it doesn't mean you are guaranteed to see and catch a Shiny.
I will breed hundreds of Pokemon when I make a team (and I even have a box of foreign Pokemon to breed with to increase chances). I have logged 600+ hours on my copy of White. I have not encountered a shiny.
I got a shiny Murkrow from a grateful friend and a shiny Eevee from last year's Video Game Championship. This year is a shiny Larvitar, but I am not going to make the drive. Most people are lucky to get one shiny Pokemon in an entire generation.
when i first started playing pokemon, my first game was sapphire. i found a shiny voltorb in new mauville. i thought it was a glitch. i ran away.
then i found a shiny psyduck in pearl.
I've never caught a shiny aside from the Gyrados...the only other shiny I've gotten was a Pawniard through the Matsuda Method (what Spoonysage was talking about) which took me at least 5 hours, and I got lucky it wasn't longer.
I have a shiny Geodude. I don't even want it. It's a Geodude. If I'm going to have something as pointless as a shiny I'd rather have a shiny of a Pokemon that I would use or I at least think is cool. The only other one I saw or seen was Zubat, but it was an ugly green.
As everyone one this page has said, it is incredibly rare to find a shiny pokemon.
I have at least 400+ hours on my heartgold and the only shiny i found was that one in the lake and that one doesn't even count.