Even if you ca't go to the ocean in person, painting waves is a fun and relaxing passtime.
Any subject is a matter of constrasting light and dark values.
The tops of ocean waves are usually white with frothy foam as they curl over to approach the land. The underside of the waves is in shadow and appears darker than surrounding water. The line where lightest and darkest values meet is the strongest contrast and most interesting to the eye. Just for fun, paint a simplified wave, Use permanent blue and burnt sienna watercolors and several scraps of watercolor paper, preferably rough. Wet the brush and mix a little of the blue and brown colors together and paint a dark squiggle line to represent the underside of the wave on the dry paper.