How do you find the central idea of an article, passage, and/or paragraph?

The central idea is basically what the over all text is talking about, so to find it you would have to read if, summarize, and find what it's taking about

You can locate the central idea by trying to find the main thing about what the article is about.

Example: Here's a teen girl, Lisa, talking to her mother. She says things like,

 "Come on mom, everybody has one." and...

"You'll be able to keep track of me. I'll actually be safer with one," and...
 
"It has a calculator on it, so I can use it in math class."

Lisa's mom says, '"Just get to the point!" 

Lisa is trying to convince her mother to buy her a smartphone. The central idea, or main point, of her argument could be simply stated as,

'I would like for you to buy me a smartphone.' The central idea isn't hard to figure out, especially when you think of how important central ideas are to our everyday communication. Also, while you are reading, ask yourself "What is this mostly about?" Or, the most important detail in the text.