A few things to try to hook people:
--Its great fun when Carrie (Claire Danes) starts cussing. She doesn't a lot, but when she does she meant that $#!+
--The stories are complex and make the viewer think but not the incomprehensible mess that most spy plot twist stories are
-- The settings are (I would guess) realistic in that a war room for example is not all slick and chromey, there's water stained ceiling tiles and cables hanging loose into a ceiling panel, etc. I would imagine that the spy craft is one of the most realistic we will see on film.
--The twists can be fun or heart wrenching
--My theory is that Shawshank is not a story about a prison break, but a story of friendship set in a prison. Homeland to me is about Carrie, Saul, and Brody that happens to be set in a spy thriller.
I'm just riding high from the end and really want to convince someone to watch.