Consider how things may look to partner

One the most inherently beautiful aspects of bridge is the partnership element. The true expert nurtures his partner; he anticipates any problems that his partner is likely to have and, if necessary, takes control. Cover up West and South’s cards on this week’s deal, and see if you can replicate East’s defence: 

 North-South have a good auction to 4♠ in which South shows six ♠s and a game-invitational hand with his 3♠ bid; North accepts the invitation with his golden ♠Q and West leads ♥Q.
Declarer plays low from dummy, you as East play ♥8 as an encouraging signal for partner to continue ♥s, and partner follows by leading ♥J. Declarer plays low from dummy a second time. Your play?

If you play low - allowing partner’s ♥J to win the trick - partner is likely to play a third ♥ hoping declarer has one more ♥ and you one fewer. That will be disastrous - declarer will trump, draw trumps in three rounds, and run dummy’s ♣s discarding all his ♦ losers.
You know you can defeat this contract - assuming declarer has more than one ♦. Simply overtake ♥J with ♥A and cash ♦AK.

ANDREW’S TIP: Consider things from partner’s point of view, and be prepared to take control if you know what to do and partner may not.