People play a few game of Blitzball and give up.Its not going to be easy straight away.You've got to stick at it for a while,play as many games as u can.Yes you will lose but every time your characters will level up.A key point is that the more a player handles the ball the more exp they get so just try swimming away from their attackers and waste the game......you will level faster

And Elaron i know what u mean about characters not leveling.My Datto who is a RF just won't level.He's still level 9 while Tidus and Jumal are level 29