2. Duplicate your ocean layer - hide your original so you can go back to it over and over quickly if things don't go the way you like with this step. I am going to do three passes of different filters, first I hit it with reticulation (foreground color is the ocean color, background color is white) set to very small values (density 2, foreground level 2, background level 5) then I immediately go to edit > fade and fade the reticulation effect to 10%. Next filter is add noise set to 8-9%, then immediately fade that effect to 15-20%. Last effect is median set to 2 pixels. What I end up with is a somewhat watercolor looking ocean. -for some added thrill you can play with the liquify filter and paint in some currents and turbulent type looks but make sure you fade effect on that as well when you are done otherwise it will look too obvious, remember to try to look painterly and a clear use of some tools in photoshop will break that illusion quickly. Layering up of slight effects goes a lot further. Here is what I ended up with:
Addendum: There is actually infinite+1 ways to do this step, this is just a quick method that I have come up with that I am happy with for getting a watercolor look. One other method that I will mention is to duplicate your water layer, apply a find edges filter to it, then change that layer to multiply and lower the opacity. This almost gives a lighting effect look to things but its can be very controllable and quick. Additionally you can add a ripple effect to this multiply layer for added watery look.