There's a few key ideas they like to point out. Here are ways you can avoid bad information:
Emotional Language: Get people fired up! Then they'll believe anything. Provoking strong emotions can increase the likelihood that information (real or not) will spread. Often it's fearmongering or something to strike sadness in you. Can you remove the strong language and reword it with less emotion? If so, it's manipulation! So watch your heart strings--someone is playing them!
Incoherence: With this one, you'll see two different ideas that try to make a point, and yet if you think about those two ideas, they don't work together or make sense. For example, someone might say, "You don't deserve to go to the mall because you have abnormally large feet." What does one have to do with the other? If someone sounds hypocritical and contradictory, trust your gut and look deeper at their discussion.
False Dichotomies: It's either this or that. Nothing in between. There is very little in life that is truly black or white, and most issues have a lot of gray area. Anyone who speaks strongly of "one way or another," be cautious and dig deeper.
Scapegoating: You may have heard of this one. Here some group or maybe an individual is blamed for something. But it's hard and usually quite unfair to blame complex issues on one person or agency. And you probably don't like being blamed for problems you didn't create, right? So if you see the blame game being played, dig deeper.
Ad hominem attacks: Oh, this one sounds tricky, but it's not so bad; in fact, it's kind of like scapegoating. Imagine two people arguing. One says, "I wish people would compost and recycle more." The second person says, "That's dumb because you're a tree-hugging hippie!" First of all, there's nothing wrong with hugging trees or being a hippy. But also, that's not a good argument for not wanting to compost or recycle--it's throwing an argument in someone's face and attacking the person. There's no real argument there, and it's usually used to distract from the issue at hand. Watch out for personal attacks.