You need to determine the resonant frequency of the glass. It should be a strong resonance, meaning a thin goblet. You will need some way to measure the resonance. If you have a microphone and an oscilloscope, you can tap the glass and measure the frequency of the ring. In spite of what you have seen on TV it is not easy to do, but if you get a signal generator and amp and play the resonant frequency very loud and near the glass, you can get it to break. I would guess that the resonant frequency of most wine glasses is in the 800 - 1500 Hz region.
So at minimum you will need an audio oscillator, amp and speakers. You can get along without the microphone and oscilloscope by listening to the ring of the glass when you tap it and trying to match by ear that same tone. Sweep the frequency slowly in that region and there is a good chance you will hit the resonance and break the glass.