Too bad luck isn't an option, because...well, it's Pokemon. To carry on from what Windsong is saying, team building is probably the biggest factor in a person's success. Not only is it important to have a solid team so that you can recover from a bad prediction or misplay, but a solid team is also important in recovering from hax. Hax is one of the most powerful aspects of Pokemon since it has the potential to override skill completely. You might run a few calculations and find that Pokemon X has the potential to cleanly sweep as long as it has enough health to take a hit from the opponent's Pokemon Y. Then you are able to carefully play your way into a perfect checkmate with just enough HP on Pokemon X to survive that attack...and then your opponent gets a critical hit and ruins everything. As long as you have a solid team, you increase your chances of recovering from such hax and possibly finding another opportunity to win the game.