Some of our teams are having problems playing and winning in doubles. This is a huge disadvantage because the 6 singles + 3 doubles = 9 matches format means that one third of the points come from doubles. So if all the players win their singles matches but lose the doubles, the opponent still gets one third of points for the night.
The following is one of the best advice for playing doubles <Click> : Doubles Tips For Table Tennis. Please read it, understand it and use the tactics for your next match!
Here is a summary:
Serve mostly short, and in the middle of the table ie, the middle dividing line.
When serving, think or ask what your partner is good or strong at. If he hates underspin balls, don't serve many heavy underspin balls which will probably be returned with heavy backspin. Try serving such that the return suits your partner for an attack.
Signal before serving.
Returning in doubles is easier than in singles, so focus in returning well, ie attack safely.
Return so that your partner is not disadvantaged. It depends if he is a looper, blocker or might have poor footwork. Set him up for a winner not for a shot he is rather hopeless at.
Your footwork depends on the right and left hander combination. See the article, or talk to a good doubles player/coach. The best combination is one Left Hander and one Right Hander since they both stay on their forehand positions.
Return most balls to one spot especially if your opponents have poor footwork.
Attack your poor opponent relentlessly rather than the better opponent if theirs is a poor/weak combination.
If you're the stronger player in your team, attack as much as possible.
If you're the weaker player in your team, play within your means, not attempting difficult shots that never go in or are easy meat for your stronger opponents anyway.
Years ago, our div 2 teams consisted of average players individually but several times we won all the 3 doubles matches and eventually got into the finals. Once in the grand final, we had a strong player who won both his singles, the other two players lost both their singles' but we won the trophy by winning all the doubles! It went down to the very last match and it was so stressful but we used our underdog disadvantage well. The opponents thought they had it in the bag because they were confident that two of our players couldn't win their singles.
It helped because our poorer players had good footwork, thought about the game, assessed weaknesses in the opponents, were good friends and focussed on every shot. Learn from mistakes, adopt better options and relentlessly apply pressure on your opponents rather than just wilfully trying to smash your way into wins.