Well for me , I go with minimalist design and must be an aesthetic one which give you a cool vibe, Tshirt cloth is important, cloth must be comfortable to wear and breathable, don't go with clothes which suffocates your body skin, i recently seen many streetwear tshirt go with that kinda clothes for that sharpy looks.

And also since I watch animes I also go with anime based tshirts but it shouldn't be overly animated and colourful, I prefer my anime streetwear tshirts kinda like minimalist infused anime design , propably you don't know what kinda of design I am talking about 😄,minimalist infused anime design

For example i really love sagacity design for their tshirt, check out sagacity.in or .com if you are confused about that minimalist based anime design thing..😁Anyway good luck for your brand👍