I have no problem with the hessian appearance per se. In fact, I look like one, and I am still pretty young so I can get away with it. To me context is important. I am not particularly worried if I am in a casual context and somebody doesn't think I look like a serious person, whatever that means. If they talk to me at all, any notion that I am some sort of drug-addled idiot is quickly dispelled. I definitely have some standards nevertheless. I have nice clothes for the appropriate occasions, e.g. dates, job interviews, funerals, weddings, dinner with the family, etc., etc. That is just common sense, I think. But I do try very hard not to look like a slob even when I am dressed casually. I pay close attention to how clothes fit me. Anything overly baggy or overly tight is out of the question. I also do not wear shirts with big colorful illustrations on them, or dumb statements on the back like "I eat children for breakfast", or pictures of corpse-painted weirdos. If I wear metal shirts they are almost always black with white logo and possibly some simple colorless album art or something. That is "hessian" enough without being overly tacky by my standards. Actually, a lot of people probably think I own only one shirt because of this. Also, a lot of people probably think I only own one or two pairs of pants given that I procure my casual lower body wear exclusively from military surplus outlets.
I do not have long hair; I shaved it all off recently. When I had long hair I would pull it back into a ponytail on serious occasions. Actually, I preferred that look over letting my hair down, and women had nice to things to say about it when it was like that. Now that I have a shaved head I look vaguely like one of those heathen white nationalist/fascist guys, especially if I wear combat boots. That worries me a bit because I have no sympathies with fascism qua political persuasion. It probably doesn't help that I don a mjollnir pendant. Well, anybody concerned that I'm a racist should know that I am a flagrant race traitor.