I have been playing the games competitively since gen 4.
Incidentally I was at the Pokemon World Championships a few years ago. I am hoping to participate this year as well to get there, but it is quite tough given I'm no longer in school and am in university now. Plus there's quite a high level of competition now, which is great.
It takes years of practice to get good at competitive pokemon. A lot of it is all about knowing every competitive moveset/stat spread a pokemon can hold. So it helps if you start playing casually to familiarise yourself with pokemon moves/abilities, etc before you move into competitive where you have to predict your opponent's every move throughout the whole match. Its good mind games. Also you can barely call random matchup on the ingame online options competitive. Yes you can get a few guys who run good spreads and have some synergy in their teams, but most people are just casuals. If you truly want to play competitive, you have to go to dedicated competitive battling sites like smogon and challenge people through Wifi.
