To avoid plagiarizing, cite sources when needed, learn how to paraphrase correctly, and feel free to use common facts and information. Talking about how fruits and vegetables are healthy is a way to use a common fact and not plagiarize. However, using a specific statistic about the health of apples needs to be cited.
When writing a paper or article, it helps to prepare before writing it. Gather all of the information and details to be included and write an outline. This not only allows for a paper that flows better and includes all the pertinent information, but it helps to know when sources and references need to be cited. Taking detailed notes instead of copying and pasting information found from online research is better because it prevents accidentally using the same phrasing.
When rewriting something in the person's own words, find a new way to explain the information or talk about. Add a personal opinion or a new angle that wasn't discussed when conducting the research. Gather information from multiple sources, using a small amount of information from each source. Good paraphrasing requires more than just changing a few words of a sentence. It requires changing the words and the sentence's original structure.