In a doubles match, the return of service is extremely important because it determines who gets the high lift first. The pair who lifts the bird first will be attacked, which means they have to make a defensive move. Most probabaly player who play offensice tend to win rallies.
Whenever you return a serve in doubles, make sure the shuttle never lifts up or slightly high enough over the net, as you will be punished. So, keep the bird always low and flat. More technically play the bird directing downwards in all the directions during return of low serve in doubles, so that your opponent is forced to lift the shuttle and you or your partner can prepare for a smash and may earn a point from the lift rally.
Technically speaking, there are three areas where you can force your opponent for a lift or weak return, so that you can finish off the rally easily and earn a point. They are play a spinning or a close net shot and hold your racquet over the net for a possible net tap or brush.
Direct the low server to the sides by pushing the serve inbetween the two standing players.
The third one requires more speed and agility so that you direct the shuttle towards the serving players body or intercept between the two players. Once the shuttle is played to the body or inbetween, defenitely you will incur a weak reply which you can finish off easily.