The first step is not accepting everything you read at face value. Start investigating the claims you see on the news or social media and you will develop a sense for which ones tend to be bullshit and which ones tend not to be, you will learn to recognize the bullshit ideas not because they're obviously bullshit at first, but because they're surrounded by the kind of language that bullshit claims are often smuggled into. It's just pattern-matching, it's a skill like everything else and you can practice it and get better. One way to do this is to just find a news article, scroll to a random point in it, highlight a sentence that makes a truth claim about something, and go 'That seems like bullshit, I'll look for corroborating sources' even if you're sure it's true. Then go do find 3-4 other sources that talk about the same thing and see how they shade things differently. Aside from learning to match the pattern you also learn which sources are more or less reliable, more or less biased, etc. A good tool for this specifically for news is GroundNews, every article they show includes ratings for how biased the source is, a list of other sources that also report on the same incident and what their biases are, etc. Plus it's been my experience that looking at things from several angles is kind of like drawing a bunch of lines that pass near the point of truth - the more lines you draw, the narrower the space in which the truth must reside, so the easier it is to find the center.

The second and perhaps most important step is being willing to be wrong, especially in public. Be concerned not about whether or not you will look bad but whether or not you are putting good information out there. Develop the habit of stopping in the middle of your political rant or whatever and going 'Wait, am I sure about this? I should check.' In a similar vein, get into the habit of providing sources for your own claims, even if only because that reinforces the habit of checking yourself. I discuss politics a lot online and have often found myself going 'Oh yeah, well

<this>

Also on the subject of sources, look for authoritative sources first. If you're investigating a claim about vaccines making people sick, for example, don't look for news articles about it; go straight to the CDC where they have data about adverse incident rates for vaccines that is publicly available. When you hear about something that happened in a particular place check the local newspapers first because they're likely to have picked up the story before anyone else and are more committed to providing accurate information that's relevant to locals than the national media, they tend to sensationalize stories less. This isolates you somewhat from some of the more egregious bias and spin out there.