Keep a running probability estimate for a market and formally update it (Bayesian updating — revise your belief by a set amount each time new evidence arrives) with every poll, stat, or on-chain signal, weighting each by how informative it is. When your updated estimate moves far enough from the market price, you trade. The edge is integrating many different kinds of evidence instantly and rigorously, while the market absorbs them piecemeal and slowly.
Markets on Polymarket where bayesian sequential-update probability engine is the natural play: