Sorry it's taken me so long to get this posted, but I'm here.
This chapter was more of infomation to understand your children, not very much as far as techniques go.
The reason to even talk about birth order in the first place is not so you can treat your kids differently because of their birth order, it's to understand how they see things. As we learned in chapter 2, behavior is based on the child's interpretation of the world around them. It's like a family is a play and children try to each fit a different character or role. If one child is the smart one, another will try to be the athletic one, or the rebellious one, or the needy one! Basically, it boils down to the oldest often see themselves as a leader, and that they must be the best at everything. The youngest tends to either expect to be pampered or strives to keep up with the older sibling(s). The middle(s) vary a lot but generally feel that they must be different in some way, which could mean being more outgoing, overachieving or underachieving, rebel, whatever. There are a lot more factors that can make these things different, like age gaps and how many and in which place and which gender other siblings are. It's very dynamic. But, the main point is that we need to help our children not get the wrong perception about themselves and let them all know they're loves. Nelsen points out that children will likely be fine being themselves rather than trying to fill a role if the parents are loving and cooperative with each other and agree on child-rearing, and if children feel they are loved and are being treated fairly.
So I guess I couldn't really put this into practice, but it helps me be aware that my children may be acting the way they're acting because of a perception in their minds of their place in this family.