This is one of the difficulties I had to overcome when I first started to draw anime. I've noticed that anime clothing folds tend to be quite sharp and 'unnatural'. In this tutorial, you'll be learning how to make folds look somewhat more 'natural'. This tutorial works with almost every type of flowing fabric.
Approx. Time: 10 mins (not very long if you have lots of practice)
Feel free to share your work! I'd love to see them! ^ ^
Step 1: Outline
Ok... So, we'll be working with a robe I suppose. You know how robes tend to have HUGE sleeves that make you want to twirl around? We'll be working with those in this tutorial. Yes, it's meant to be an arm. Ignore the fingers cause this tutorial is about the sleeve. Start by drawing a right triangle for his extended arm. This is used to guild you.
Step 2: Top Bumps
As stated before, the anime style tends to have sharp edges rather than smooth flowing ones. Give the sleeve a few bumps like the ones next to the neck and hand. It's kind of like a letter 'L' sideways or upside-down. Note that not all bumps have to go INTO the fabric. For example, look at the bump second from the hand. It kind of just stays above the arm and doesn't dig into the fabric. Of course, in almost every type of clothing, you will see smaller bumps. So go ahead and add in some zig-zag lines.
Tip (Cloth): Take a long piece of cloth or clothing and drape it over your arm. Make sure the cloth is longer than your arm length. Push the end of the fabric up to your wrist. Right now, you should have one end at your shoulder and another at your wrist. Examine the folds. It might help a little.