I think that when you are doing street evangelization, or when you are explaining the Marian doctrines to someone in really any setting, you should be able to answer the question, “Why should I care?” In other words, “What does this mean for me? How can this change my life? Why isn’t it enough to simply take it or leave it?”
With some of the Marian doctrines this is easy for me to answer. For the doctrine of Mary as the Mother of God, I should care because this means that I have a mother who cares for me. For the doctrine of the Assumption, I should care because in her I have the guarantee of the resurrection that I too will experience if I persevere in grace. For the doctrine of Mary as Mediatrix, I should care because this doctrine means that, if Mary, a mere creature (although a highly exalted one) can cooperate in Christ’s saving work, then so can I. It means I have a role to play in bringing about the subjective redemption in the lives of people.
But, why should I care that Mary was conceived without sin? Why should I care that she was a perpetual virgin? I’m drawing a blank on these two. I realize that ultimately, I should care because these doctrines are true, and I should want to believe whatever is true. But, I want to be able to give people something more than that.