Alternatively, scan your drawing into your computer. Use art software to trace your starfish.
You can create hatching or cross hatch marks with a soft pencil, like a 4B or 6B. You could also use water-soluble pencils and roughly shade over an area and then go back over the pencil with a wet brush to fill in the area.
If you’re mixing colors, experiment with different hues and ratios until you get the desired tone.
