My girlfriend loves romance shoujo manga. She prefers if they had quit a bit of romance, love triangles, handsome guys, and preferably from a girls perspective (at least most of the time) she also loves when they're about vampires or just fantasy in general with school life and drama.
Some of the mangas she has read
Fruits Basket
Ouren High School Host Club
Tokyo Mew Mew (Both series)
Kamichama Karin (Both Series)
Vampire Knight
Bloody Kiss
Hyper Police
My Girl (The one about the model)
Sailor Moon
Ranma 1/2
Rosario+Vampire
Spice and wolf
Please only completed manga
Some of the mangas she has read
Fruits Basket
Ouren High School Host Club
Tokyo Mew Mew (Both series)
Kamichama Karin (Both Series)
Vampire Knight
Bloody Kiss
Hyper Police
My Girl (The one about the model)
Sailor Moon
Ranma 1/2
Rosario+Vampire
Spice and wolf
Please only completed manga