One of the most important things adoptive parents must do is actively bond with their children. This seems to come easy for some parents, but is more of a struggle for some of us. We don't get the normal infant years where we carry a nursing child and do other things that helps make a deep bond with our child. Even if they come young, we will have missed out on much of the early bonding that most families take for granted.
Some of this is time. Some is physical contact. Both were a bit at odds with how I was raised. While my parents spent time and weren't afraid of appropriate touching, they were more private individuals and we definitely were not a touchy-feely family. My own personality is much more of a loaner, so I tend to isolate myself more, something that is not as helpful when raising children.
I mentally wrestle with how much impact this had on my children. While they definitely had many convinced that I was the source of their problems and would certainly blame any shortcoming, I am not convinced that this was the entire issue.
Still, I wish I had wrestled on the floor with them more when they were young, focused more time with them, etc. As with most parents, I would redo some things if I could and I would put this at the top of the list.
I am not sure if it would have provided the bonds I wanted though. They had enough things keeping them in their own little world, but I do wish I could have tried it more.
As I noted before, don't wallow in this. You can't change the past, but we can try to help others do better in the future. That is my aim here.
So work on bonding, even more than you would with children you had given birth to. Getting through the walls your children erect will be a challenge, but it is worth it, for their sake!