A royal priesthood

1 Peter 2:9 "But you are a chosen people, a royal priesthood, a holy nation, a people belonging to God, that you may declare the praises of him who called you out of darkness into his wonderful light."

The term royal priesthood is a struggle for me, I have no frame of reference to really understand what it means.

The elements of crown, rule and sovereignty are obviously key parts of the biblical sense of royalty--they are talked about a lot, including being used often in the descriptions of God and Heaven. Yet the concept of royalty remains distant because even the modern example of British monarchy doesn't quite fit due to their lack of true power. And really, most of us aren't even familiar with what it means to be a modern (relatively powerless) king or queen. 

Priesthood implies some aspect of outreach. In the Old Testament, the priests were intermediaries between God and his people. They were the ones who made sacrifices to God on behalf of the mass. Then again, priests also extended divine forgiveness to the people. 

This much I understand: being set apart as a royal priesthood, we serve duo functions. On the one hand, we present God's rule and sovereignty, showing what God is like to the world; on the other hand, we serve as intercessors for the lost.