Step 10: Draw the dolphin's head using the big arc as a guide. Make the head a bit thinner on the bottom and darken the top part.
Step 11: Using the triangle as a guide, draw the dolphin's flippers. The flipper should curve more and the base should bend toward the inside of the body. Draw the flipper on the other side of the dolphin's body by drawing a small curved line to the left.
Step 12: Draw the dolphin's dorsal fin by using the other triangle as a guide. Curve the shape back a bit.
Step 13: Use the last triangle as a guide to draw the dolphin's flukes. Draw a curved line on the bottom and a curved line on top. Then join them together at a point near the middle.
Step 14: Use the remaining lines as guides to draw the rest of the dolphin's body. Simply darken the outer lines to create that sleek slender dolphin shape.