Plagiarism is technically defined as: 

The action or practice of taking
someone else's work, idea, etc.,
and passing it off as one's own;
literary theft.

Source: "plagiarism, n." OED Online, Oxford University Press

So what are the different types of plagiarism you should watch out for? 

The types of plagiarism information is from the Butler University Plagiarism Guide.  

The easiest thing to do is to always cite your sources. If you question whether something is "common knowledge" or something you came across in your research, find a source for it and cite it to be safe. 

As you go to include your sources, you'll find yourself using one of three methods to add the information into your paper: 

1. Quoting
2. Summarizing
3. Paraphrasing

Here's a bit more about how to properly do these and make sure that you're avoiding plagiarism: 

Direct Quotations

These should be used sparingly so that your voice is showing through the paper. Use these if: 

• the wording of a quote is highly technical
• it's important to show the exact wording (e.g., in an interview or a debate)
• you're analyzing or interpreting a passage

Make sure that you're citing in-text AND in the works cited/reference list. 

Summarizing

This is the big picture of a chapter, article, or even entire book. You're condensing the main points, ideas, and/or support into a few lines. 

Make sure that you're citing in-text AND in the works cited/reference list. Even though you're not using quotation marks, you'll still want to cite in-text with the author's information and pages (if they're relevant; if you're summarizing an entire book, you don't need page numbers). 

Paraphrasing

This is the easiest way to plagiarize, but is the method your professors will want to see the most. This is where you're taking a sentence or a few sentences and putting them into your own words. Essentially, you're synthesizing what was said, showing that you really understand the material. The more time you spend with the material, though, the easier it can be to think that a piece of information about the topic is common knowledge, when it's really from a source. It's better to cite a source than not if you're questioning if something is common knowledge or not. 

Make sure that you're citing in-text AND in the works cited/reference list. Even though you're not using quotation marks, you'll still cite this like a quotation, with the author's information and page number(s). 

Tips: 

• As you're reading the text you want to summarize or paraphrase, underline/highlight quotes (if it's your copy), or make notes on the information you want to include. 
• In your notes, take those lines and put them into your own words. 
• Make sure to jot down the page numbers/citation for each! You don't want to have to go back through everything all over again to find that information. 
• When you're writing your paper, paraphrase/summarize from your notes so that the wording is more of your own than the author's and is a true paraphrase or summer that isn't just repeating what the author said. 

Text version of this flowchart. Link to view the larger, original posting from The Visual Communication Guy.