The best way to avoid plagiarism is to cite the sources of the information you include in your document. In other words, you need tell the reader of your paper where you obtained the information. This applies to things you read (books, articles, web documents, pamphlets), see (videos or DVDs, online videos, television programs, charts/graphs, illustrations, photos or other images), hear (radio programs, lectures) - basically, anything that is not your own idea and is not common knowledge.
Is This Plagiarism? Test Yourself! Try this online tutorial from Simon Fraser University.
The Library's guides to documenting sources using APA shows you how to cite your sources properly in your essay. For examples of citations in the Reference list for different types of sources, see the Library's APA Guide.
SFU's APA Citation Guide for Business Sources includes examples of citations for annual reports and statistics.