If possible you should drop your political opinions altogether and do your best not to follow any political ideology. You can still form opinions on various issues if you feel the evidence is very strong one way or another, so long as you've given consideration to both sides, but if you believe in an ideology which offers easy, pre-fab opinions based on some overarching "philosophy of government" you will be hopelessly biased when approaching something new. Ultimately this bias will infiltrate how you perceive every issue, including cultural and personal ones (see how nasty and personal presidential politics always gets.) Basically, politics destroys the mind.
This is admittedly an almost unreachable ideal, but if you want to avoid bias it has to be the conscious goal. A nice side effect is that, since nobody has time to study and consider every issue, you get to be comfortably neutral on most of the things people tie themselves up arguing about.
Homer: [looking at watch] Two hours? Why'd they build this ghost town so far away?
Lisa: Because they discovered gold over there!
Homer: It's because they're stupid, that's why. That's why everybody does everything.