Gotta find reputable sources to scan. Really, that's the magic.
I have Hubski, The Daily Beast (Cheats page), Vox.com, BoingBoing (they are totally nutty, but they link to sources religiously), The Economist, The Two-Way (NPR's version of the Daily Beast's Cheat page), etc.
And then I regularly check reputable news sources like Bloomberg, Reuters, The Guardian, The Independent (RIP), and BBC World News.
You also gotta check in on the the enemy and see what they are saying. So I read The Week, The Federalist, anything put out by the Heritage Foundation, and other frothing loons.