it always depends on what kind of girl is she. if she's nice then be nice and helpful. if she's. funny then laugh at her jokes even though it's not funny. if she's smart then help her on homework or ask her to study with u or on a test or u acn ask her to tutor u.
Do you really like her? Think about it. Is it worth starting a relationship with this person? If you believe so then ask them out. But if you don't know the person in real life then perhaps it isn't worth it. Plus she could be anyone.