Hmm well for the p4 girls I had more of a... theme? I guess? Like Chie was sort of knight themed and Rise idol themed. Whereas the p3 girls I've been basing more on their persona's appearance without a set theme in mind, maybe that's the difference? Other than that I really don't know!
There really isn't, it's such a shame! I mean I love p3 and p4 but the other games deserve some attention too. >A< These are actually really easy to draw once I get the design down, so they're sort of stress relief for me. ^^