Question

What causes waves in the liquid particles in a lake, ocean or sea?

Answer 1

Most of the time: wind.

The rest of the time:
- convection flows
- things falling into the water, such a birds, rocks, children, rain
- for the oceans: tidal activity
- seismic activity, such as the Tsunami last year in Japan

Answer 2

are you talking about shallow water waves.? (Those circular waves on the surface). They occur in shallow water bodies like lakes. But in oceans and other deeper bodies, we get those large waves we can surf on.
These waves are caused by disturbances mentioned above. The disturbance travels, when water molecules that are excited hit others. The ones are hit then hit the ones next to them. The result is a circular(or elliptical) shape expanding with time. It eventually dies out, when the energy gets diminished due to damping as a result of repeated collisions. Though the water particles appear to move, they just stay there.
You can read more about this on http://electron9.phys.utk.edu/phys135d/modules/m10/sound.htm