Introduce direct quotations with your own words. After quoting, explain the significance of quotations. Avoid quoting more than is needed. Most of the time, brief quotations suffice. Use direct quotations only when the author's wording is necessary or particularly effective.
Some disciplines discourage direct quotations.
Check with your professor. Be sure to copy quotations exactly as they appear. To avoid any unintentional failure to cite sources, include all citation information on notecards and in your first draft. At all times, stay in control of your argument and let your own voice speak for you. If possible, have a clear question in mind before heading off to the library so you will not waste time taking extraneous notes.