Clothes can be tricky to draw. Some are rustic, some are thin and transparent. So making a tutorial out of it is also somewhat difficult. For this one I chose a variety of textures to explain, but the main tutorial will be on a Still life piece. And read until the end, because there's a surprise for you!
(1) I start with a rough sketch to place the idea. The background is dark since I want the result to give the spotlight to the clothes.
(2) Once the idea is doodled, I work on the lineart. The cloth on the background is supposed to be rustic, so I will not add too many folds, unlike the one hanging from the jar, which is gonna be thin. I also add some flowers for the aesthetic.
(3) Understanding the folds: The jar is standing on a stool, and the cloth from the background is covering it. The folds will meet and lead to the front, where some of them will twirl on themselves as the fabric naturally laid down. A reference picture can bring more light to the idea, since the position of the clothes are variable (meaning that they don't tend to fold the same way).
(4) To distinguish between clothes, I paint the background one pale, and the one in the jar red. Now, this is not just randomly chosen (see Extra at the end of this piece).
(5) I add the shadows and lighted areas. Light will come from the left side, so the shadows on the rustic cloth will be darker the closer they are to the focus. To have a guide in mind, coloring folds works like this: base color - light - base color - shadow - base color.
(6) I blend the folds using the Finger Tip brush, lines from top to bottom. If needed, I strenghten the bright areas with a soft brush.
(7) I use filter layers to portray dramatic lighting. First, a Multiply layer, duplicated from the merged piece, to create deeper shadows. Then, Overlay layer, full colored in a grayish, pale orange, to give it a feeling of an ancient work.
(Extra) Still life setups have hidden meanings, so I will uncover this one's, even if it's not too relevant to this guide (takes notes, this is gonna appear again in the future of my tutorials). White usually symbolises purity, but this one is not white. It's grayish, looking old, rustic, bigger, and under the jar. It represents the lower class. While the red one, thin, brittle, smaller, and coming from inside the jar, represents nobility. The jar, then, represents riches. But beauty is represented on the darkest area, with the flowers. Visible but at same time hidden, what lies in darkness can be more appreciated in light. They represent Life - past, present and future.
Here's a list of fabrics. It doesn't include all of the existing ones, but it will show the most common textures. Along with them I added a painting with folds, to show how light and shadows work in each. You can click on the pictures to make them bigger and see the textures. An obvious coment that I would receive out of this is "But this doesn't show me how to draw it!". Fear not, it's way easier than you expect it to be. This table is not to show the differences, but the similarities. Some of them are semi-transparent, some are soft, others are rough. When you choose a texture for your character's clothes, you are the one deciding how much detail you're putting into it. But, if it helps, with clothes like Chenille or Tweed, it's always a good idea to follow a pattern of squares (which all clothes have, but usually so small it doesn't show).
To finish this tutorial/guide, I prepared myself a basic Still Life setup for you to study and practice. To start, look at these photos (a) and (b). They're taken from the same angle, but the direct light was placed on the left for (a), and on the right for (b). This can give you an idea on depth, since the difference between the pictures is noticeable.
Now, it's time for you to practice. Feel free to take the following photos - (c) and (d) - I took, to paint them yousrself! This is just for study reasons, but if you create an entire original piece with it, I'd love to see your work! And if you feel brave enough, you can even change the fabric texture!