Easy "Sky High" achievement
Host a private match. Join a team and have another person join the opposite team. Have the other person continuously hit the ball high in the air. Get an Aerial Hit by hitting the ball in mid-air when it is higher than the goal. Afterwards, have the other person get a self-goal. Start an Exhibition match and hit the ball above the goal line. When the "Aerial Hit" message appears, pause the game and choose "Change Team". Then, score your own goal to get the "Sky High" achievement.