How to find my half sister?

[Hannah]

Does anybody know how i could find my half sisters from my dads side. I know their names and their mothers name but i don't know what they look like or anything? And even though i know their surnames they could have changed it with being married?
Any suggestions could be what i need!
Also, I have already asked my mother and father about them but nobody knows much about them. I haven't got any grandparents or aunties or uncles to find out more.

[...]

facebook is a good place to start. But you will prob need to know what they look like to track her down through a profile picture. I tried to find my sister & the companies to help find people didn't help at all. The electrol roll is good aswell, if you know the area she lives in and a last name

[Ellie]

you could always ask your mom or dad or someone in the family your aunt,uncle,granda,grandpa anyone would help if they dont know or dont want to tell you search them up on google or try to figure theyre email or phone number or write them a note that should get you guys connected