If I may just scoot in here and offer some tips! Recently I redesigned my own UTAU from
this to
this. So I think I can offer some advice that helped me out.
Even though her first design was a simple one and basically just borderline re-imagined typical Vocaloid/UTAU elements I still managed to make it special and make it mine with the color scheme and her flowers. Take the flowers away and turn it into a monochrome color scheme and she wouldn't have stuck out much. Still, it worked and got her from 2011 to now(well...that plus her voice).
These days in the fandom, new UTAU who just use the same old Crypton-loid design elements are not going to get far. If you see an UTAU with that design style and they get a lot of attention it's probably because they've been around for a looong time where something like that was okay and expected.
For my UTAU's second design I looked up a lot of different outfits and clothes designs to get my ideas(while also re-imagining some elements from her old design which on their own were re-imagined bits of the Crypton-loid designs...). And of course she has her flower...
So, my advice to you would be to think about your UTAU as a character and what kind of clothes would she where if she weren't an UTAU and were just a normal original character? Part of her own story if you will cause honestly she already is, ya know?
- Where is she from?
- What kinds of colors does she like?
- What's her favorite season?
- What would she wear during that season?
- Does she like to dress in a feminine way? Or more masculine? Casual? Formal?
- What kinds of accessories would she wear?
- Does she have a symbol or theme or something that could set her a part from everyone else?
- Is she a happy character? Does she hate everything? Neutral feelings towards living?
I could go on....and a lot if not all of these things don't even have to be canon. You also don't have to answer all of them; but they can and often do affect what someone would wear and could help you come up with design ideas. Google some images of different fashions you'd think she'd wear for reference. Don't be afraid to mix clothing styles up! Make sure your color scheme conveys the feelings you want it to. Obviously for my UTAU, it's clear she's a sweet and nice person from her pretty pastel Spring-time colors.
Black + one other color is nice and all and can convey a more neutral feeling and character...buuut....after a while the schemes start repeating themselves? You should try adding some other colors to her design.
Understand? And don't give up!!! It takes time to come up with a good design that people will find interesting and set your UTAU a part from the others. Character design come naturally to some, not so much to others. But your UTAU is off to a decent start, friend. You just need a little push in the right direction!! ^^