I've been reading Patterson's books of Alex Cross and his detective work both as a DC cop and now an FBI agent. There's a couple of things that really stand out in his work for me at least. One is that I can hear Morgan Freeman talking in my head when Alex is on the jizz and two is how well Patterson creates the relationship Alex has with his kids and Nana Mama. I hope and I try like hell in my writings to do the same thing. The personal relationships and their clarity and significance is important to me.
I can remember in my first novel "Day or the Dogs" the best relationship in clarity and significance was that between Dr. Bob and his father. His father was probably the furthest from a main character but that's probably the most talked about by my readers.