Many instances of plagiarism are unintentional and can be avoided by pacing your work appropriately, carefully documenting your research, and using citation practices that clearly differentiate between your own ideas and contributions of others. As always, your teachers and the librarians are available to give you guidance if you are unsure about how to cite information in any paper, project, report or article.
Carefully follow any written or verbal instructions provided for a paper/assignment (this includes peer or tutor editing/advice, whether this is a collaborative project, or if outside sources are permitted).
Pay attention to dates and pacing. Leave yourself enough time to work thoughtfully and avoid citation errors often made when rushing.
Generally, you will not need to cite “common knowledge” in your papers. If you can find the information in three sources, especially a general reference source like CREDO or the Encyclopedia Britannica, it is probably common knowledge. If you are not sure, a good rule of thumb is that if you learned the fact while doing research, from any source, cite it.