Proceed along the way of the Rosary.
That is to say, start with the Angelic Salutation, in St.Luke's Gospel. Remember the Angel salutes her saying "Hail, full of grace, the Lord is with thee". St.Thomas says that it was absolutely unheard of in antiquity that an Angel should reverently salute even a man, and the Old Testament instead shows us Abraham and Lot reverently saluting Angels, even prostrating in veneration. This shows us that Mary most holy incomprehensibly exceeds even the just of the Old Testament. It also indicates her Immaculate state, since where grace is full, there is no sin, and this even before, as the Angel describes next, the Holy Spirit indissolubly united Himself to her forever as His most glorious Spouse.
Continuing with the same Gospel, come to the Visitation. St.Elizabeth, much much elder to the Blessed Virgin, is amazed and humbled by the visit of the Mother of her Lord as she says when filled with the Holy Ghost. St.John whom Our Lord styled the very greatest of the Prophets, leaps for joy in his mother's womb. This again bears witness to the unspeakable greatness of Our Lady.
There is much more that could be said, for from Genesis through Revelation, there is scarcely a time when the good God, so greatly wounded by the transgression and malice of our first parents, was not thinking of Our Lord and Our Lady. For in the very day they sinned, it was said to them by the Father, in Genesis 3:15 "I will put enmities between thee and the woman, and thy seed and her seed: she shall crush thy head, and thou shalt lie in wait for her heel." Note that Protestant translations typically corrupt this text, but the first part remains untouched, so that even they must confess that the fallen Angel Lucifer is to be conquered by a Woman and her offspring, who will be the new Adam and Eve. Who is this Woman if not she who is blessed among women? For, if the offspring is Christ, it is manifest the Woman can only be Mary.
Finally, come to the Assumption and Coronation. In St.John's Apocalypse, the last book of inspired Scripture, we see in the twelfth chapter, a Woman radiant with the splendor of the sun, with the moon under her feet, crowned in heaven with a majestic Crown of 12 stars, present there in body and in soul, unlike the disembodied souls we saw earlier in the same book awaiting the day of judgment patiently. She is the Mother of God (verse 5) and the Mother of all Christians (verse 18). St.John again recalls our mind to that ancient serpent as he shows the Woman and her offspring at enmity with him. He shows us that the dignity that Eve lost, to be the mother of humanity as such, was instead given to Mary, to be the Mother of redeemed humanity, that is to say, of Christians. Lest we did not understand the meaning of that action where Our Lord gave Mary at the Cross to be the Mother of the beloved disciple, St.John here explains it for us. Mary is to be the Mother of all Christians without exception. He cannot have God for his Father who will not have Mary for his Mother.
The last verse of the preceding chapter also calls her the new Ark of the Covenant in heaven, which is also important, since the Ark of the old Covenant was to contain the word of God, was greatly revered by the Israelites and irreverence to it was punished by death, as happened to Uzzah. Now, as the Fathers point out, Mary is the Ark of the New Covenant, since she held the Incarnate Word of God Himself in her womb, and is therefore forever holy and unstained, and the slightest irreverence to her is therefore utterly intolerable to the divine Majesty.
So devotion to Mary began at the Cross, and to the Cross will it inevitably tend as to its last end. Devotion to Mary is the most perfect and excellent means to love Christ and Him crucified. Who else ever loved God as Mary did. She was first at the Cradle, She was last at the Cross. Let Protestants love Mary as Jesus loves Mary and only then will they come to love Jesus as Mary loves Jesus, and as He wishes to be loved, and then they will be drawn by Him into the one true and Catholic Church.
The following video points out some of the more profound insights of the holy Fathers into the passages of Scriptures, including some of what I've related above
Several of my Protestant colleagues, who came to me trying to make me believe in their own ideas, now accept that the Blessed Mother is crowned in heaven, by the grace of God. Some Protestants are of bad will undoubtedly, others are just ignorant, and have never heard Catholics defend the sacred doctrines of the faith as taught by the Church.