The most important factor for internet research is the subject. If your subject is too broad, you will find too much information. If it's too narrow, then you may not find enough information. More than a few hundred hits on a given search is too many. Subject matter is also important in deciding where you will look; information in the humanities will not be found in the same places you find science-related information. Try a variety of search terms, playing with wording and using synonyms. You also want to keep the purpose of the research in mind as that will determine what information you need. A research paper for an English class requires different information than a chemistry lab report.
Learning to evaluate a source for validity is an essential part of learning how to do research. "The Wadsworth Guide to Research" advises that Wikipedia might be a good place to start when considering your topic, but it is considered a weak source because anyone may change the entries. Check the URL of the web page. If it is ".edu" then it will likely be legitimate, as will URLs that end in ".gov". The most viable pages to reference will include outside citations. These citations not only give credibility to the page, they can be valuable sources of additional information. Your sources should come from reliable writers and web pages. If you aren't sure about a page, then check the information against other credible sources.
A number of schools, especially colleges, give students access to libraries and databases that aren't available to the general public. These typical include internal webpages that are only accessible by students or faculty, journals or other publication collections, electronic editions of books and subscription research sites. This list is by no means exhaustive and each school offers something different, so you will need to explore a little to get the most out of what your school offers.
There are a variety of commonly used documentation styles depending on your subject and the preference of your school or teacher. As pointed out by Diana Hacker in "Research and Documentation in the Electronic Age," writing on a subject in the humanities will likely use either Chicago style or MLA (Modern Language Association) style; business writing tends to use the AMA (American Management Association) style guide, and many of the sciences use the CSE (The Council of Science Editors) style manual. Each style brings its own formatting requirements for the paper, and you will need to know which you're required to use because it will change how you document your Internet research.