Before reposting something, ask yourself “have I heard about this website before today (or before this news event/cycle)?” If you haven’t, google the thing you just read about, and see if you can find an article from a source you’ve heard of before today.
This isn’t to say that mainstream news doesn’t get things wrong, they definitely do sometimes, but so much of the real garbage I see on social media is people all sharing the same post from some random site called like newsline.xyz or something. In fact there’s so much low hanging fruit like that that I think a large amount of disinformation would go away if people just checked if anyone at all was reporting the story other than the source they’re reading.