Welcome to Fluther.
Great question.
As others have stated, you can learn some of this through formalized course work, and it’s a good way to do it. But you can do a lot of it on your own, too.
For one thing, you can look up any number of links to describe and show the most common logical fallacies. You’ll have to keep looking after that to become more familiar with their application, but once you’re turned on to them it’s hard to turn that kind of thinking off (and that’s a good thing).
And here are some other considerations:
– Journalism (at least the way it used to be taught and applied) insists on factual reference to “time, form, place and event” as well as “who, what, when and where” and teaches questioners to be alert for missing data. (For example, and you can see this every day on the web, people post links to various events – which are undated. When you examine those you often find that although they are presented as current, they happened long ago and have been resolved. That’s a kind of lie.)
- Look up Richard Feynman’s address to the CalTech graduating class of 1973 (seriously). It’s called his “Cargo Cult” lecture. It’s brilliant and still applicable.