They Keep Returning to Your Partner? Change Where You Serve
Some matches you barely touch the ball. Every return goes to your partner, they get worn down, and you stand there feeling useless.
It is rarely a coincidence. The return direction is largely decided by where your serve lands, which means it is something you control rather than something that happens to you.
Serving from the far side: aim at the side glass
When you are serving from the side away from where returns keep going, put the serve into the side glass.
A ball coming off the glass pulls the returner wide and opens the angle back towards your half. Then cover your side, because that is where the ball is now most likely to come.
Serving from your own side: aim at the middle
From the other side, do the opposite and serve into the middle. A middle serve takes away the returner's angle to the outside.
With the wide option gone, the straightest and safest reply is back towards you rather than across to your partner.
You are steering the return
Neither of these guarantees anything. Returners can still surprise you. But over a match you shift the odds considerably, and that is enough to change who gets worked.
Your partner stops being the target, you get into the rhythm of the point, and the pair stops being lopsided.
Ask why, not just what
The habit worth taking from this is bigger than the serve. When something keeps happening to you in a match, look for the shot of yours that keeps causing it.
Most patterns that feel like bad luck are patterns you are feeding.