Well, firstly, men's T-shirts should differ from women's in style. For example, women's T-shirts should be pretty cute and men's T-shirts should be brutal. For example, in an army style or something like that. You can see a few examples at
https://lionlegion.co.uk/. There are many cool and brutal T-shirts out there. Or if you do something in common, that is, in the same style, then you can just draw a website logo. I think it will look pretty good. The guy a little higher threw off this logo, I think it is not very bad. Or you can make several types of T-shirts at once - classic (just with a logo), a T-shirt with a funny inscription, and something like that. In any case, something interesting will turn out.