Words of praise and encouragement go a long way. If you play frequently with the same partner, you will develop a rapport and understanding. Unrated Rooms are perfect for practicing strategy and technique with a new partner. The competition is usually good, and most of the players are congenial. Then you can move on to rated events.
Successful partnerships exploit the errors of their opponents.
Many a lost game has been rescued in this fashion. Let's face it - you cannot count on having great cards every game. If the opponents are equally matched or stronger than you, your best chance is to play solidly, and avoid errors. However, if you are the superior team, and the cards are unkind, then you must wait for those opportunities to pounce on the opponents' miscues. Psychology and intuition are part of any game.