Ok. I may not a be pro or even close but I have been reading manga since a lonnnng time ago, so I hope that helps. BTW I read Bloodroot it's pretty cool and I love Netsozou Trap.
Anyway, let's go the point. I think one of the main differences in the shoujo drawings is the round eyes **, **the eyeliner (or eyelashes? lol) and the frilly wavy doll .like hair and a rounder face. Also a smaller nose and mouth.
Something like this I suppose? (I am guilty of shamelessly redraw it just to make me unsderstand )
Anyway I do like your drawings :), and I suppose the more "femenine" character of Bloodroot is Tina not only because of her assets *cough * you can see her lips, round eyes, lot of eyelashes lol, and and smaller nose (I think).