What is the fastest way to increase a property's value?

Publish on the decision-stage queries you already rank near, and make the conversion route reachable from where that traffic lands.

Most established properties have second-page positions on the comparison, pricing, and alternatives queries in their subject. Those are cheaper to move than new terms and they carry the money. The second half matters just as much: intent-carrying traffic frequently lands on pages built by one person while the contact route was built by another, and nobody ever compared the two.

What is not fast: authority. It moves on the scale of years, and the main thing that builds it is being useful about the same subject long enough that stopping would be noticed.