CAS ideas: how do you flesh out your adult sims?

Pretty much the same as simgirl1010​ 
Before I introduce them to the intended sim, I play them in a separate save. I work on skills, career to a decent level and work on their likes and dislikes by how it's going for them. No money cheats cause I like the struggle at the start .
I don't use story mode mainly because one time I've seen it ask something about liking pets iirc, and despite saying no it gave the sim the cat lover trait. So just cause of that, I can't trust it make a sim for me.