Making a second character is really useful for keeping patterns (I have my clothing patterns on my main one since they're the ones I need for her, then stuff like paths I keep on my side characters). They're also helpful if you need to reserve an area of your town for something but don't want it to be a PWP.
I'd put her in a spot where you'd like to have something other than villagers, PWPs, or empty space. You can turn that side character's house into pretty much anything, like a hospital, a school, or just a spare house of sorts for your main character. Be creative! That character's house doesn't have to be house-like in any way so you can use it as a way of having a little extra in your town.
What else... name your character something you like, if you're going for a theme pick something related to it. It's your choice so we can't help you much there. I just picked names I liked and fit with the general "vibe" I was initially going for in my town.