The return of serve sets the shape of the point. A return without a clear target can give the serving pair an easy first volley and allow them to settle at the net.
A simple default is to return with purpose, often deep, so the server has less time and space to move forward comfortably.
What to do
Depth matters because it can delay the server's movement and buy the returning pair time. Once you have created that time, be ready to move forward together rather than admire the return from the baseline.
You can also use a lob return when the situation is right, but the same principle applies: the return should have a tactical purpose.
Why it works
Think of the return and your next movement as connected decisions. Choose a target, watch the quality of the shot, then react as a pair.
A good return is valuable because of what it lets you do next.