Christian marriage has both human and religious dimensions, and the Church needs to form and prepare engaged couples in both.
However, as between the two dimensions, not only is the religious the more important (in fact, it is the informing principle, or the “soul” so to speak, of the human dimension) it is also the one in which the Church alone has a pre-eminent competence. 
In other words, an engaged couple can learn well just about everything they need to know regarding the human dimension of marriage – e.g., good communication skills, good budgeting practices, good parenting principles, etc. – from reliable secular sources, and we should feel free to refer couples to them. 
However, with respect to the religious dimension of marriage (i.e., its core sacramental identity and the moral obligations that flow from its identity) it is the Catholic Church and the Catholic Church alone that can teach them what they need to know.
And so, though we should give due regard and attention to the human concerns of marriage, we should spend a greater proportion of time and attention on the religious. 
As the Pontifical Council for the Family wrote in their 1996 document, Preparation for the Sacrament of Marriage“It is essential that the time and care necessary should be devoted to doctrinal preparation.  The security of the content must be the center and essential goal of the course…”

Still, throughout, our program focuses on many different life-skills, linking them to the spiritual because we consider the Person as whole (body/spirit/soul):

First session: the reading of Genesis eliminates any confusion about our life’s missions as male and female.

Second session: St. Paul teaches us how to communicate and live as husband and wife.

We also focus on forgiveness, one of the most important skills in marriage!

Third session: we approach chastity, family planning.

We also discuss what discipline is about and give resources on child rearing.

Fourth session: we go into the more “traditional” type of life-skills such as potential problems, communication, conflict resolution, budgeting, and expectations.