When playing, an easy way to charge up the ball is to use 2 players to pass it to eachother repeatedly at the back until the ball turns white,then lob pass it to someone further up, and take a first time volley. For this to have maximum effect, I recommend using one or two playmakers to pass it at the back(such as Toad or Boo), and using either a captain(such as Wario or Bowser Jr.) or another sidekick with high shooting(such as Birdo or a Hammer Bro).