Start with simple shapes like circles, ovals, and lines
Draw the basic body outline of the animal
Add fins, tails, flippers, or tentacles
Sketch the head, eyes, and mouth
Refine the body shape and proportions
Add details like scales, stripes, spots, or texture
Erase extra guide lines
Outline the final drawing with a darker pencil or pen
Color the animal using suitable ocean tones
Add water, bubbles, coral, or seaweed if desired