When I ask my friends to pray for me, it is not because I believe that their wills match God's Will. Coupled with the "Queen of Heaven" business, it really does not appear that Mary's intercession is anything like asking a friend to pray for us at all.
Sometimes I do, other times I ask Jesus through Mary,
I wondered about this answer. If one could pray directly to our Lord Jesus for help, why would one want to ask a "friend" to help?
That is why the intercessionary prayers of Mary are much more effective. "The prayer of a righteous man are truly effective". Why? Because God's will be done. When a person prays that God's will be done, it is more likely that his prayer will indeed be answered. Thus, since Mary's will is perfectly united to her Son's, we have a powerful intercessor.