I'm interested in the aspect of politics where the political agenda is set and how certain ideas become mainstream and take hold.
Are there any works on this worth looking up?
Read about Antonio Gramsci. An Italian Marxist arrested in fascist Italy, Gramsci's 'Prison Notebooks' are some of the most influential political analysis works of the last century.
Despite being written about Italy specifically, the theory of hegemony offered by Gramsci seems to be along the lines of what you're looking for. He is a Marxist, and there are internal contradictions, but his work is pervasive and has influenced a lot of thinking in the west.
in my opinion this is brilliant work: http://www.amazon.com/Three-New-Deals-Reflections-Roosevelts/dp/0312427433