Making Amends with Maven Black-Briar - True Thane
As Thane of Riften you will be able to have one of your guards shake down people and demand they hand over some of their stuff to you. Be careful, however, if Maven finds out you've been shaking down her citizens, without her permission that is, then she will not stand for it. She will demand compensation and, if you continue to work this way, there will be other consequences.