Polymarket on resolution odds vs. actual trading? Feeling stuck.

Been dabbling in Polymarket for a few months now, mostly on bigger political events and crypto resolutions. I get the concept of probability markets, but I'm still struggling to consistently size my positions. Sometimes I see a market at, say, 70% for an outcome, and I'll jump in, only for it to swing hard against me. My issue is less about being right or wrong, and more about how much to commit when the odds are already established. Do you guys mostly fade the extremes, or do you bet into the established consensus, hoping for a small edge? How do you think about position sizing when the market itself is the odds?