What is the best way to prepare for the total consecration to Mary?
read True Devotin to Mary.
Copying from the text you provided.
a) Preparation: While, strictly speaking, a consecration could be made merely silently and interiorly, by one act of the will, yet it is far better to make a preparation, and to make the act itself with the recitation of a good formula, even with some solemnity. The True Devotion book of St. Louis de Montfort contains in a supplement one concrete form—others are quite possible. It includes 12 preliminary days, followed by three weeks. It can be very helpful.
b) Living out the consecration: There are several ways to describe this. We will propose a synthetic presentation, for the sake of clarity. We could sum it all up by saying that it calls for a spirit of union, a spirit of dependence, and a spirit of obedience to her.
Mary is God’s dream of humankind.
May we find in her - the fertile soil of humility and the wheat that grows a thousandfold- Jesus, her son.