If my daughter's dad walked out on her when she was a year old and  Ihaven't heard or seen him in 11 years, how do I get his parental rights terminated?

You need to seek legal help here.  Was there ever an established order of paternity or an affidavit of paternity or acknowledgement?  If you were never married then you are technically the child's custodian unless there was such an order.  Now, you can move to terminate his rights.  It can be a difficult proceeding to do. But it is not impossible.  And you are going to have to make an effort to locate him and its okay if you don't, as long as you try.  That is for service of the paperwork.  Good luck.