In doubles play, the tactic is to serve low so that the serving side would not be placed in a defensive position. If you are serving low, take position on the front and part of the midcourt area immediately.Your partner shall then cover the back court. This is known as the Attacking Formation (Front-Back).
You can also use the flick serve to prevent your opponent from rushing to the net. But you and your partner will have to take up a defensive position standing side by side. This is known as the Defensive Formation (side-side).
When you defend, try to hit the shuttle deep into your opponent's court. This is to prevent your opponent in the front position intercepting the shuttle from mid to front court.
When a chance presents itself, push or drive the shuttle to the area in between your opponents. Or make a return to the front court of your opponents, forcing them to lift the shuttle.
In this instance, the player who played that shot will have to take up the front position immediately while the partner takes the back. An attacking formation shall be formed. If you are taking the back position, your aim is to make shots that can create openings for your partner to 'kill' in the front court.
In all types of doubles play, teamwork is the key in forming a formidable partnership. Although an ideal player will be skillful in all areas of the court, most will either show greater flair around the net or be more effective with overhead shots.
You and your partner have to figure out how to make the best out of your skills together. Play to your own strengths and your opponent's weaknesses.
You will find this much easier if you communicate well with each other. Do not leave it to guesswork! Talk to your partner. Is there a leader in the partnership or is it all a matter of shared responsibility? A quick word on court might change the result of a game which is slipping away from you.
Remember...Teamwork is the success formula in doubles!
article source: http://www.badminton-information.com/badminton-strategies.html