3. Put the trumps to work

Tempting as it may be to win A♣ at trick 1 and trump a club at trick 2, this will result in defeat with West playing a 3rd round of clubs when in with A♠, eventually giving West a second promoted trump trick. Trumping with the long trumps, though sometimes necessary, does not gain tricks. Trumping with the short trumps however does gain. So, win A♣ and at trick 2 play K♥ then 9♥ to A♥ and trump your 3rd heart. Now draw trumps. West can win A♠ and play a 2nd club which you trump. But you still have three trumps left, enough to draw all of West's remaining trumps, before enjoying your diamonds.