This page is meant to assemble some information and guidelines that students may consult about writing papers. It is not anywhere near complete yet. Comments are welcome.
You will be called upon to write "papers" for much of your professional life. The "papers" - using the term broadly - may be as diverse as term papers, qualifier papers, theses, research papers, surveys, white papers, business plans, and design outlines. The remarks below are mostly geared toward the first several - more academic - categories, but some of the remarks would apply to any professional writing that you do.
Writing a paper should not be viewed as a chore, but as an opportunity to organize your thoughts. Often, organizing your thoughts - even if about well-known topics - is a good service. Even if no one else benefits from this exercise, you will. You will often hear people say that they did good research on some topic, but could never get around to writing it up. They may be sincere, but they would often be mistaken. In most cases, the fact that they didn't write it up means that they never quite completed the work. In writing it up, they would probably have realized what holes there were in their arguments - the experiments they didn't run or the theorems they didn't formulate and prove. Research writing is more than just a narrative of the steps you took, but includes some assessment or evaluation of the ideas you proposed and developed.
The importance of writing in good research is one of the reasons for the CSC graduate faculty's decision to change the format of the Ph.D. qualifier exams (aka written prelims). Official information on the this exam exam is available here.
Quoting others verbatim is usually not a good idea anyway. First, what you say or write is for a purpose, and your purpose in your paper is very likely different from the original authors' purpose in their paper. Therefore, even when you present their ideas, you have to present them in a way that fits with what you are talking about now. Second, mixing different styles of writing and interrupting your flow with lots of quotations does not help your reader.
Indeed, there is usually little reason to quote others verbatim, unless they have an especially pithy saying that you must include or they made some especially specious claim that you must present as is before you tear it apart. For the above reasons, quotations must and can usually be replaced by paraphrases (see below).
Of course, not every idea in a paper will be - or should be - original. You will almost always build on the work of others. However, you should describe the work you build on. If you do it in your own words, it is called a paraphrasing and is generally acceptable. By the way, it is not acceptable to simply reorder some bullet items, or make minor grammatical changes like converting a sentence in the active voice to one in the passive voice.
Unless the work being described or paraphrased is well-known - that is, part of the "folklore" - you should credit the people with whom it originated. In general, as topics become better known, you should cite expository writings describing them, e.g., textbooks, handbooks, encyclopedias, or survey articles. For topics that are relatively recent, it is better to credit the originators directly.