My sister owes me $7000 which is a large sum for me. Can I place a lien on her home to guarantee that I will eventually get my money back.

How would I go about doing this?

First you need to file a lawsuit against her. Then you need to win a judgment. With that judgment order you may file a lien against her property. There is no way to get around going to court and having a Judge issue a Judgment.

There is one other way... if your sister signs a mortgage and you have the mortgage recorded in the county clerk's office.