> The challenge is how to create the water wave outside the bottle ( on the skin of the bottle ).

The key thing is to try to draw a curve that is a profile of the shape that you want. Then you use one of the construction commands to create your object based off of that profile.

In this case revolve is good, but there are also other tools available as well, like Lofting through cross-sections, or sweeping along a path. These methods allow you to make a custom shape guided by the profile curves that you draw.

- Michael