Hmmmm....I don't think that there's really any specific things you should keep in mind when inking water. There would be more in the way you handle the coloring stage, depending on how realistic you want it to be.... The only think I can think of is that the surface of the water should be relatively smooth, not really wavy like it seems to be in the rough lines you've made. The surface tension of the water and the fact that it's a still pond (or how will you see the ripples!) would mean that most of the motion of the ripples would effect the lines horizontally and not vertically (more side to side and less up and down). Hope that makes sense, it's pretty late. lol
I read somewhere else that you were using the pen tool to do this. Very ambitious of you, lol. Some people favor it, but I absolutely don't - I usually don't see results worth the effort - so I just use the brush tool. I think if you really want to use a vector tool to ink, better to just do it in flash or illustrator (imho) But definitely a great technique to build patience and technical skill.