When doing research the most important thing to do is to stay organized. Cite sources as you use them and manage your citations in folders. Bookmark the pages you need to refer to and always make sure you get information from reliable sources. Don't be afraid to question the source's bias and their conclusions.
Conduct backward and forward searches.
A backward search is a search of the citations of the references you used. If you find an article particularly useful, check through the article's references list to find more information relevant to your topic.
A forward search is a search of the articles which cite an article you use. If an article has a high impact factor (it has been widely cited) then there will be a large pool of relevant articles which you can search through to find more information.