Politics are very real to people. They aren't to me, but I know those people who can't shut up about it. Most of my friends are Libertarians, which I suppose stems from the need to be an "exotic" conservative. I am more of a pessemistic Christian Socialist, but I have been present for their long winded debates predicated on a universal hatred for the common man. Then again I think the Justice League should be free. The role of man in society dominates their lives. So how do we get this energy and passion into our stories? Funny you should ask...
Politics may not be the crown jewel in world building, but it's up there. Creating a socially political environment in your story should be brainstormed before you actually start the story. What the politics of the world manifest as will influence the character, but it will also make the story more real to the reader. Imagine why there are so many WW2 buffs out there and you will understand this concept. Our grandparents were deeply affected by political changes in the mid 20th century, and what the state decided immediately changed the way the people lived their lives. Today that isn't the case, as technology has proliferated our society. Creating a world without a social net (fishing net I mean), the characters will not be held back from experiencing lives affected by politics. It'll also add a "drama factor" to your book. Like Orwell's 1984 we will know the sufferings of the common man, in the throes of unavoidable change.
Setting up a political system in your book starts with creating a party system. It doesn't matter how many you create. What matters is that there is more than one. Each party must me unique and not just a regurgitation of the same principals. What makes a political party unique are their stances and individuality. If you consider how hot political debates are in this country, one can only imagine what it could be like were there more parties. In a two party system there will be fierce competition and backbiting, just like it is in this country. In three party system there will be a progressive party, a conservative party, and a minority faction with aggressive tendencies. Were you to have a party system greater than four, be prepared to lose clarity of social divisions. In these worlds you would probably be dealing with a Galactic Senate situation ala Star Wars. Consider that the Star Wars Expanded Universe is an unfolding drama on Micro and Macro scales. There is the Galactic, big picture drama developing on Coruscant and the smaller conflicts fueled by passionate in fighting across the worlds. Politics is all about scope, and if there is too much going on, you will be lost and so will the reader.
How to construct a functioning political milieu in entirely up to you, but I will offer some advice of what factors to consider. One thing that I have noticed is that class disparity has existed throughout the course of Human history and will continue to do so unless something "cataclysmic" happens. What this disparity produces in an unskilled proletariat, a much smaller specialized class, and a tiny ruling class. Older forms of government thrive off of conceptions that the lower classes are too stupid to rule themselves, and hence a Monarchy derived from political consolidation of the upper tiers of society is born. The Divine Right of Kingship is a religious permutation of this concept, except the power to rule is chosen by the divine hands of fate. If your classes are more spread out and there are narrower gaps between the class distinctions in your story then you could be more democratic. Democracy creates strife and tension by having many people of the same caliber existing side by side in political union. Civil wars are common in Democracy, and birth factions and groups of people bound by some common principal. Because Democracy predicates it's operating beliefs on the inclusion of the common man into the political decisions of the larger nation, I would recommend your story be centered around a younger protagonist that is grappling with their identity within this world. Democratic unions are interesting because it places the burden of performance on the individual to carry their weight in society. Also, characters can be lost in translation, forgotten, marginalized by the larger social network that develops in the political climate. Older societies will operate with a group mindset (a struggle for the kingdom's fate) and modern societies will showcase the inner spiritual conflicts of the protagonist.
Politics determine your story's development and social schemes. Work on developing a diversified political realm before you venture out and work on the rest of the book. Don't brush this off! A good story understands the nuances and complications society can place on the protagonist/everyman. Focus on how many parties, or factions, will constitute your world. Understand that the amount of parties presented to the reader will determine the political environment and how the characters will operate in society. The form of government you ultimately land on will have an impact on the characters, and how they conceive of their existence. Monolithic institutions like a Monarchy or an Empire will drive nation focused narratives. Democratic institutions will produce people focused narratives, and contemplate the individuals that compose society.
As always, take your time. Make it count for something. The world depends on it!