Use MultiSearch:
Green: appropriate resources for your essay/assignment.
Orange: may be appropriate; consider carefully where the resource was located, how reliable it is, and why you are using it. Use sparingly.
Red: Very unlikely to be appropriate, unless identified by your lecturer as a resource they wish you to look at.
The internet has a lot of useful information, particularly from governments and organisations. Check who wrote the page you're on:
Try Google Scholar to find reliable journal articles, or the Advanced Search features of Google to restrict your search to results from reputable sources.