The explosive spread of information with the spread of the Internet has had the unfortunate result that almost anyone can present himself as an authority in almost any field. This makes it important to train students to discern the reliability of their research sources before depending too heavily on the information they gain from those sources. Encourage students to seek out verified experts in the field, to use reputable reference works and to apply common sense as they evaluate the claims and analyses they find while researching.
An important way students can help ensure the reliability of their research is to check multiple sources before drawing a conclusion or defining a thesis. While you do not need to hold students to unreasonable standards of comprehensiveness, especially at younger grade levels, encourage them to find at least two or three sources that deal with their topic. If they can find multiple points of view, it will round out their understanding of the scope of their inquiry and help them develop a more-informed opinion.
Citing sources is a skill that some students have difficulty learning, but it has great importance when it comes to writing an informative, ethical research project. Clear citations that follow the designated standard format make it easier for a reader to verify claims and to study further if a particular point stands out as worthy of additional inquiry. Enforcing relevant citations will keep students from slipping into lazy habits of generally citing an unread but related source, habits which may harm them in the future.
One of the most fundamental guidelines for an English paper is that the student must provide original thought and analysis, and must give due credit where she uses the work of another author. Maintain a strong standard in this area by teaching students what does and does not constitute fair use. One technique that may help well-intentioned students keep away from inadvertent plagiarism is to do whatever reading and research they plan to do for a particular section of the paper, then put away the reference works as they write the section to ensure non-derivative language.