How can I double check my work for plagiarism?

The most important thing you can do is to understand what plagiarism is and so knowing how to not plagiarize. However. There are many helpful tools for you to utilize, one being Google. Copy and paste a couple paragraphs into Google and see if there is an exact match. Furthermore, there are many programs out there that their sole purpose is to check for plagiarism, such as: WriteCheck, DupliChecker, etc.