I'll show three different seascapes, step by step. You can either follow them all, or pick one or two. First one is a quiet sea on the beach, we'll see how to paint the sand and sky with gradients, mimic the reflections of light on the sea.
Second one is moving water on rocks. We'll see how to paint the light in the wave, mix accurate colors, render the rocks, and have fun with the crushing water!
Last one has a loose style, almost abstract, to render the vortex and movement. We'll see how to paint loose.