When in doubt, cite all sources. It's important to be mindful of source-based plagiarism and other types of plagiarism.
Double-check all secondary sources to make sure that the original source actually exists--that way you're not reproducing someone else's misinterpretation of facts or events.
Make it clear who said what. If you're mixing your own ideas with those of your sources, be sure that you distinguish each of them clearly.
Avoid assuming that what you know is "common knowledge". When in doubt, cite it.
Learn how to paraphrase. Change both the words and the sentence structure of the original thought or idea. Keep in mind that the paraphrased passages still require citations because the ideas came from another source, even though you are putting them in your own words.
Take notes with the same citation habits you intend to use in your paper. Use signal phrases;
Learn how to cite sources properly in your discipline (APA for social sciences & business).
Employ a citation manager like Zotero to keep track of all of your sources.
Purdue University. (n.d.). Best practices to avoid plagiarism. Purdue OWL. https://owl.purdue.edu/owl/avoiding_plagiarism/best_practices.html
Turnitin, LLC. (2021, August 2). Preventing plagiarism when writing. Plagiarism.org. https://www.plagiarism.org/article/preventing-plagiarism-when-writing