Samuel Sweet: Shiny surfaces are so because they are literally scratch-free. Even the smallest scratches refract light and make a surface seem dull. Two things can produce a super finish like you are describing: a high gloss finishing buffer or a UV-cured finishing gloss.
To create a glass-like finish with a buffer, it is important to understand graduating your grits during finishing. I finish my applications with a 240-grit buffer, apply cuticle oil, buff with a 1,200-grit buffer (which removes all scratches), wipe any free-standing cuticle oil off with a touch of nail cleanser, and then buff with the high-gloss finishing buffer.
Using a UV finishing gloss top coat is another popular option. Finish filing your application with a 180-grit file, cleanse the surface, apply the UV finishing gloss, and cure the nail under the UV light.
The finish created is permanently shiny and solvent-resistant. The only potential downsides are that it contributes to the thickness of the enhancement, requires filing off, and makes it slightly more difficult for cuticle oils to penetrate.