Sakura is the main character. Her story begun when she opened the misterious Clow Book (for further information see Story) releasing the Clow Cards and waking up it's guardian (Cerberus a.k.a Kero-chan) Sakura is the one who goes looking around, hunting for those Clow Cards. When she catches a Card, she can borrow the power of it when catching other Cards. Kero-chan became her guardian and close friend, he helps her to catch the Cards by giving her tons of advice.
Sakura lives with her father Fujitaka and her older brother Touya because her mother died. Touya likes to annoy Sakura by calling her monster, she really hates that. Sakura likes Touya's best friend Yukito alot, so she always goes to school with her brother to see if she is lucky enough to see him.
As the story goes by, we discover she has a rival in both, catching the clow cards and for Yukito's attention, his name is Li Syaoran, he is a misterious transfer student from Hong Kong. This boy has a lot of knowledge about the Clow Cards and he has magic powers too, he acts a little bit rude with Sakura first, but later he becomes friend with Sakura (he even helps her catching the cards sometimes!!) and he ends up liking her! *spoilers* at the end of the 3d season she finds out and starts blushing whenever he's around ^_^.
Sakura is a kind hearted girl that unlike her mother she is great at sports and we can find her often in the chearleader team, cuz she's a member of that team. Her best friend is Tomoyo and some of her classmates are Rika, Chiharu, Naoko and Takashi.