Step 20 (optional): Erase as much as you can of the initial guide lines for a cleaner look. Don't worry about erasing all of the guides. It's okay to leave some behind. Re-draw any final sketch lines that you may have accidentally erased.
Final Step (optional): Add some shading to your orangutan 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. Add the value lightly at first, then gradually build up to the level of darkness that you want. Continue shading and vary the pressure on your pencil to get different degrees of tonal value.
Add a cast shadow underneath. This helps ground the orangutan so it doesn't appear to be floating.
You can add more value throughout your orangutan drawing for more detail. Orangutans have orange-red fur, so you can color your drawing instead if you'd like. The fur doesn't have a pattern, so use a single value for the entire body. Use smooth strokes for the face but don't shade the fur too smoothly. The rough value creates a furry texture. Add the value by using strokes that go in the general direction of the fur. Continue adding strokes until the entire body is covered. Shading can be time-consuming, so be patient and take breaks. Don't forget to pause the "How to Draw an Orangutan" video after each step to draw at your own pace.