Citing your sources properly -- yes, even the websites and images you use, and the videos you quote from! -- is important and required.
Purdue University's OWL Writing Lab citation resources are the best ones out there on the web. Guides for MLA, APA and Chicago style are available -- check with your professor about which citation style you need to use for each particular assignment.
Diane can help with citations, too!
Perhaps the most important resource you'll need to rely on when researching are scholarly (and often peer-reviewed) journal articles. These are harder to find on the open web, via a search engine like Google. Instead, start in some of these databases to find scholarly journal articles. If you find a record for something that isn't full text, you can request a copy through InterLibrary Loan.
There are also many subject-specific databases that you can find on our Databases A-Z page. Use the "Subjects" drop-down menu to filter the list by different subject areas.
It can also be useful in the course of your scholarly research, especially if you are looking at current events or a topic that is related to popular culture, to find newspaper and magazine articles -- popular sources written by journalists and reporters. Though you'll likely want to focus more on the scholarly articles for any academic research, these shorter, contemporary articles can be a useful addition. Rather than searching the web, the library's Lexis-Nexis database compiles thousands of newspapers and magazine articles, and makes searching for and finding them far easier.