That's a bit difficult because I already go into anything from The Onion knowing it's intended to be humorous/satirical.
What I lack in ability to recognize satire or outright deception from posts written online, I make up for by reading comment threads: seeing people accuse things of being fake, seeing people defend it as true, seeing people point out the entire intention of a website is satire, seeing people who had a joke go over their heads get it explained... relying on the collective hivemind to help me out where I am deficient. It's not a perfect solution at all, especially since people can judge wrong—I bet some "omg so fake" threads were actually real, and some astroturf-type things written to influence others without real experience behind it got through as real.

Feels weird reading this as the only single woman programmer in my friend group who likes men