I'm going to be completely honest, but visuals tend to catch my interest
as for stanning factor... idk it just clicks
usually I already like a member beforehand, and if the rest of the members I end up liking, then I start stanning
for the most recent groups I stanned, I liked ningning since late 2016/early 2017 ish along with yiyang and lami, and then karina early 2020 when I started actively following the public trainees, and giselle I found interesting enough early october last year; it was a kinda natural progression to stanning them
mystic rookies, I think I had a mutual who was super into them, and I found tsuyoon's friendship super cute so I ended up following the rest of the group lmao