Every object has a frequency at which it wants to vibrate. Find it, and the object comes alive — energy builds, amplitude grows, the thing begins to sing.
This is how opera singers shatter glasses, how soldiers break bridges by marching in step, how a child learns to pump a swing.
Move slowly. Listen. When you approach the resonant frequency, you'll feel it before you hear it. The closer you get, the more the object responds.
Seek the frequency. Find the resonance.