Though the book of Deuteronomy is a large and compositionally complex book, do not let that deter you from preaching it; it is far too important theologically to leave alone. The fact that it teaching and theology is so central to the rest of the Old Testament means that much of the Church's mis-understanding of the Old Testament has to do with the failure to understand and to preach Deuteronomy. I think it not unfair to suggest that if Deuteronomy has not been preached through in your church in the last decade you are looking at a church with an unbalanced spiritual diet. That said, it would be unwise to plan a ten-week marathon through the book; unless you are, or can find, an exceptionally skillful preacher, your congregation is guaranteed a spate of spiritual constipation or, worse, they may be put off ever wanting to hear you preach again.
The book of Deuteronomy is a unified work, but there are a number of seams that divides it into three or four thematic segments that we may use to structure our preaching progamme. Here is a suggestion:
A useful approach is to have a parallel programme of preaching and teaching, say, four/five sermons running parallel with another four/five classes in the adult Bible classes, or mid-week expositions.