This may sound very simple, but in doubles here are two concepts that will pay off.
When you are being attacked in a doubles point, try to return the ball to the opponent who is farther away from you.
When you are in the offensive, try to attack the opponent closest to you.
When you are being attacked, that places you in the defense. You will have just a small amount of time to defend. If you hit back to the closest player you will have less time to stay in the point.
When you are the attacker, you are in the offensive. When you return that ball to the opponent who is farther away from you, you will give him or her more time and court distance to hit a lob over your head to stay in the point. Not good.
In my 30 years of teaching, I find it is easy to teach a player in the offense to hit to the closest opponent. It takes a lot of practice and concentration to teach a player to hit the ball to the opponent that is farther away when being attacked.
Think about this before you get to the court. It is hard to change a losing habit. Keep thinking on the court. All players know after a while when they are being attacked. Do not fight it. Just defend the ball back to the opponent that is farther away. It will change the way you defend and compete.
Good luck on the court.