Actually you don't need any specific skill.
Having the skills is helpful if you want to spare some money. But basically you can get/buy all the clothes, wigs, eyes, shoes accessories and even furniture from other people.
And there are people who have honed their face painting skills to amazing heights that offer their services too.
I got lucky and had a faceup artist offer me two of the faceups (Qian and Yuki) for free, just because they wanted to practice on other brands heads too.
I myself, since I'm a tailor, making clothes seemed the most reasonable thing to do
I even sell them in Etsy. It helps me fund my life and hobbies.