The best way to play spoons is to hold your iPhone on its side and rotate the phone up and down to make the spoons clang. Spoons uses the iPhone accelerometers to determine when to make a sound. Note, that there are many hardware limitations in place. For example, if you shake the phone, the accelerometers may register when you are least expecting it because they are sensitive to changes in multiple directions.

The slight delay you experience between touching the screen and seeing a spoon respond comes from the iPhone touch-screen sensitivity set by Apple. This is an unalterable hardware limitation set by Apple at this time. To compensate, touch the spoon a few seconds early, or play using the accelerometers (by tilting the phone on its side). :)