As the others have said, the tow capacity was set based on an engineering evaluation of several factors. Without know what the weakest (most limited) component is, you have no way of determining what to improve, even assuming that an improvement is practical.
However, be aware that the limit is not in any sense absolute. The vehicle doesn't break just because you exceed the limit by 1 lb, or even 100 lbs. Nor is it foolproof simply because you stayed 1 lb under the limit. Mechanical stress and wear & tear are on a continuum and don't magically change from OK to Not OK at a single point. The tow limit represents an engineer's judgment of a point where an average driver with a typical production vehicle, driving in typical conditions, begins to suffer more than average mechanical stress & wear. There is inevitably a lot of "windage" in that estimate.
Also be aware that there is no promise that you will like driving the vehicle even when staying within the tow limit. Being within the vehicle's mechanical tolerances doesn't guarantee a no-white knuckles experience, especially if road or weather conditions get poor.