Water is really simple as a basic PBR material. Glossy with IOR 1.333, dielectric fresnel, and refraction. The trouble is with refraction rendering, all kinds of different approaches possible, with different performance implications. Also, when any wind or physics gets involved, then you need simulation and volume…
I think generally it would help if you tried to explain in more detail what exactly you want achieve using what application/renderer, ideally with images/examples. If your talking about game art, I would probably start by looking for sample/existing content for which ever engine you want to use, as linked by Neox, and then…