It is necessary to learn some formulas, but the formulas are relatively simple, and the general junior high school mathematics level can be mastered. As long as you master the prototype painting method of clothes, then change according to the style on this basis. To make western-style three-dimensional clothes, there is usually a dart transfer, and it is not particularly difficult to learn by heart. Relatively speaking, it is more difficult to draw the collar and fix the complex folds.

If you learn to draw, you can sew, not just draw the clothes you want to wear. The drawing of clothing must conform to the structure of clothing. Design is a very emotional thing. Although orthodox study will help you sum up some regular things, I think inspiration is very important.

I hope my answer can help you a little.