Some people don't just express themselves through their appearance, and that's fine. You don't
have to if you don't want to, are too lazy to care, or just don't feel like it. Not everything you wear has to be a statement of who you are, what you think, and how you view the world. For a lot of people, it's just not a priority in their lives. So long as it's all clean, not full of holes, and at least fairly well put together, that's all that matters.
If you're an artist, let your art speak for itself. Don't try to drag people into talking to you because you're dressed funny, you can actually do the opposite. Don't reinforce the stereotype that artists dress weirdly because they're artists. You can turn a lot of people away from you if you're deliberately trying to be weird. Ever seen those episodes of What Not To Wear when people are REALLY outlandish and they always say "I just think it's interesting. People will find me interesting if I look like this" and it never actually comes across that way. If you have Netflix, there are at least two seasons of it up right now, go watch it. I get the feeling that that's what you're trying to do. It's not who you are, it's not what you're about, you're just too shy and unaware of how to get people interested in you and talking to you, so you think that dressing in weird and strange ways will draw more people to you when in reality, it just violently turns them off to you.
That being said, you CAN dress alternatively or "oddly" and still make it look good and allow people to approach you. I've been alternatively dressed since at least late junior high in one way or another. I figured out that no matter what I did or how hard I tried to fit in and be trendy and fashionable, it just didn't work for me. I wasn't built for it physically, nothing fit me right, and nothing felt right when I wore it. It just wasn't comfortable, physically and mentally. I broke out and started wearing things I liked, doing my makeup how I liked, and emulating other people I thought had a look I wanted to go for (tried not to directly copy, but took inspiration from them). Over the years, and through much trial and error (the internet and it's vast collection of blogs, Youtube tutorials, and resources wasn't a thing when I was growing up, so mostly error), I've sort of perfected my look and how I want to be. It's not really a statement against the world, and it's not really a statement of who I am. It's more a statement of "I find this pretty/aesthetically pleasing/interesting. If you do as well, great. If not, screw off." NOTHING I do is for the benefit of other people. I do what I do because I like it. If others happen to like it as well, cool, let's bond for a moment over that. If they don't like it, then just walk away.
I was at a small local show last night, mostly pseudo-hardcore metal teenagers (can't really be hardcore in the middle of rural northern very heavily Mormon-centric and influenced Utah, sorry), and I had several girls approach me with awe-struck faces and say "Wow, you're so pretty!" I don't really know how to respond properly to that, even after all these years, so I just smile and say thanks as politely and sincerely as I can. One of them asked me about my makeup, what products I use and how I do it, and we had a little conversation about it. Another asked me if my kitten skull necklace was real, where I got it, how much it cost, etc. Again, another nice little conversation. You can use your looks to attract people who are already attracted to the things you do, does that make sense? Someone who likes unnaturally colored hair would be more likely to approach you and maybe want to make friends with a potentially like-minded person than someone who doesn't like it. And those are the kind of friends you want.