When you paraphrase, you restate someone else's ideas in your own words. It allows you to maintain the flow of your writing by reducing the number of direct quotations.
Text taken from another source must either be in quotation marks or paraphrased. Either way, you must still acknowledge the source in your bibliography.
Paraphrasing tutorial: Ann Barrett and Robin Featherstone designed this five-minute tutorial for Dal Libraries to get you on the road to proper paraphrasing.
Paraphrasing examples (Princeton University): The writer presents an original passage about how Hamlet reveals his madness in Shakespeare's great tragedy. Then, he gives three examples of how the original work is cited, from a word-for-word copy to skilful paraphrasing that maintains the ideas of the original without the language of the original.
Plagiarism: What It is and How to Recognize and Avoid It: More examples of acceptable and unacceptable paraphrasing from Indiana University's Writing Tutorial Service.
Paraphrase: Write it in Your Own Words: It's harder than it sounds, which is why practice makes perfect. Try these exercises from Purdue University Online Writing Lab.