I tend to come at it with a personality in mind more than an appearance. My next character is significantly less obviously crazy though... Some people have caught onto to the character flaws I baked up into this one though.
My current character personality wise, I just decided on a few personality defects. A fixation, and a personality disorder. Still developing them a bit, its always a process for me.
Uhm, visually my first character was based on the Wendy's logo, to the point that I got comments on it ICly.
My second character has a lot of inspirations as far as looks. I'll list the main three.
Ruby Rhod from from the Fifth Element for general posture and demeanor.
Ryuko Matoi from Kill La Kill for attitude and style.
https://en.gfwiki.com/wiki/NS2000 For extra inspiration.
I'll admit, I go a bit nuts with it at times, and I don't know if I should accredit it to luck or skill, but I'm really glad with the way things have turned out so far in regards to visual representation translating also to the overall image of the character.
All that being said, I'm thankful to have found inspiration through one picture especially. If it hadn't been for this one image, I probably wouldn't have had such a solid grasp of the concept of where I was going and it's certainly helped me actualize various parts of the character into a cohesive form. Though there is always fear of being derivative, I like to think I took a somewhat unique concept and made it my own, but that's really up for the playerbase to decide.
It might be a bit on the nose, but maybe you all can appreciate it and perhaps even find your own inspiration and methods of character development from the image that's resulted in me having such a fulfilling experience as a player: https://i.imgur.com/ey0DlfX.jpg