How can I get to know this girl ?

[Brotherhood]

she sits across the room in my global class and i can see her straight on because there arent any desks blocking.shes really pretty and today i saw her at a fair and she was sorta in our group but later it split in 2 and i didnt see her after but i look at her sometimes in class. and she rarely looks at me but when she looks in my direction its more of an observation than a sstare or something, idk i forgot but i wanna talk to her. she seems quiet from what ive observed. ugh idk i only have one classs with ehr and shes not on facebook and shes across the room so how can i talk to her ? its gonna be weird since we never talked to each other before at all. im so shy to say hi, ugh shes so pretty