What is the best way to persuade ad agency execs to promote your magazine to their clients?

I have a Christian Magazine in Baton Rouge and I am trying to partner up with ad agencies here so they can promote my mags to their clients. What is the best way to gain favor with them so my mags will be among the first they suggest? Need help from my marketing people out there! Religion and advertising, don't usually mix, it may be difficult to get your magazine promoted, due to the Christian theme. You can mail a copy of the publication and ask if it something advertising agencies would consider promoting. Recommend that you mail copies of the magazine to churches and residents of Baton Rouge, to see how they respond and offer a one-year free subscription to new subscribers.