Step 15 (optional): For a cleaner look, erase as much as you can of the initial guides. Don't worry about erasing all of the guides. It's okay to leave some behind. Also re-draw any final sketch lines that you may have accidentally erased.
Final Step (optional): Add some shading to your blue whale drawing to give it more dimension and volume. Pick the direction of the light source when shading so that the shadows are consistent with it.
You can add more value throughout your blue whale drawing for extra detail. Vary the pressure on your pencil to get different degrees of tonal value. Try to add the value smoothly for a sleek feel instead of a rough texture. Shading can be very time-consuming, so be patient and take breaks. It's a good idea to use reference for a more accurate blue whale drawing. Don't forget to pause the "How to Draw a Blue Whale" video to draw at your own pace.
Finish your blue whale drawing by adding a few long lines under the mouth to indicate the grooves on the throat.