Ok, of course starting with the finest materials and having the guitar built by the best luthier would also improve your acoustic guitar tone, but for those more realistic or on a budget check this out.
Replacing your stock guitar’s plastic Saddle and Nut with ones made of harder material and custom fit for your guitar will add volume and clarity to any acoustic guitar you have, even lower priced models. In our shop we use either bone or corian for both saddles and nuts. These are hard materials that can handle guitar string pressure and wear, and will transmit the strings’ energy to the guitar top and body where it belongs.
It is a basic concept but a harder material will transmit energy(in this case vibration) more effectively than a softer material that will dampen and aborb more of the vibrating string’s energy.
For more detailed information check out my article on this topic at our FAQ and Tips section of our website.