There is only one absolutely guaranteed way of avoiding plagiarism and that’s by doing all the research and writing work yourself. Don’t trust a peer or any other form of help to do the paper for you. Conduct your own research and make notes. Taking proper notes is extremely important. You cannot quote an authority or from a previous paper without mentioning who it is that you are quoting, and from which paper, journal or book have you picked up the quote.
Giving credit is extremely important to the original writer. You must copy the exact words and enclose them in quotations and mention the name of the author and assign a reference number. Using quotations in academic research papers is very important. You use them to either strengthen your own argument, or you disagree with the author and want to prove your own point. In either case you must do a complete research and make sure that your notes are complete.
Never depend on someone else to do your research work for you. This is fraught with dangers as you may end up with incomplete research, which will be very dangerous for you. Also remember teachers get to recognize their students writing styles. If you submit a paper written by someone else, it will immediately ring an alarm bell with the teacher. He or she might out rightly reject your paper or call you in and ask you to explain it. You can be sure you will get caught and punished, therefore don’t trust someone else to do your work.
Once you have completed the draft of your paper; run it through a good plagiarism checker. The checker should pick up the quotes and mark them as plagiarized. Make sure to complete the references section in the style that is required and do make sure you have used the correct referencing numbers in your paper.
Doing your own work from start to end will give you the satisfaction of knowing that you have not plagiarized and are aware of your research.