what type of tatics are you looking for and for what age?  how to zone, better footwork, defending space or player, leaning over the ball, learning what your opponent does, watching movement down the court and predicting play?  if you give me something you want to work on, might be able to help, otherwise i could be here all day explaining what tactics you could be teaching only to find out they are 11 and most are beyond them at this age.