Step 20: For a cleaner look, erase as much as you can of the initial guide lines. Don't worry about erasing all of the guides. It's okay to leave some behind. Re-draw any final sketch lines you may have accidentally erased.
Final Step: Add some shading to your harpy eagle drawing for more detail. Use a dark value for the beak and the area around the eye. Leave a bit of the beak blank for shine. Use a dark value for the feathers standing up and a light value for the rest of the head. Vary the pressure on your pencil to get different degrees of tonal value. For a more detailed guide on how to shade, check out this tutorial: How to shade.
Use a dark value for the bird's neck but leave a few patches blank for a few white feathers. Use a dark value for the wing too. At the bottom, leave a few strips blank to emphasize the individual feathers. Add the value lightly at first and gradually build up to the level of darkness you like. Use a dark value on the harpy eagle's tail to create stripes. Use a light value for the underside of the body.
Use a slightly darker value along the bottom of the body to create a shadow. Use a dark value for the talons but leave a strip blank to represent shine. Shading can be time- consuming, so be patient and take breaks. It's always a good idea to use reference as you draw. Don't forget to pause the video to draw at your own pace.