Keep the commanding card of your adversary's suit.
This the beginner invariably refuses to do; he is too anxious to take a trick and does not realise that he will often gain several by passing.
Before playing the commanding card of your adversaries' suit, wait—if you can—until the leader's partner has played his last card of that suit; he is then unable to return the lead, and there may be no card of re-entry in his partner's hand.
Rarely refuse to take tricks with your Kings and Queens.
When an entire suit is against you, it pays to take the lead; the adversaries may change the suit.
When you see in your hands enough tricks to win the game, always take the lead.
Always take the lead when doing so makes a card good in either of your hands.
Play for the longest suit in the two hands.
After taking the lead, count the cards of each suit in the combined hands and make it your object to play for the longest. It may sometimes be necessary, in order to lead the suit to the best advantage, to wait until it can be led from the other hand.
With two suits of equal length, play for the one in the hand that has cards of re-entry.