This tutorial video gives some tips on searching Google Scholar, including using the "Related Articles" link to find similar and cited articles. Most databases, such as JSTOR, ProQuest, and others also typically have "References" links that will list items from the bibliography of an article that are also in their collections.
Here's another tutorial video from NCSU Libraries on how to "chase citations" forward in time -- in other words, how to see who has cited an item that you find in Google Scholar. Library databases also typically have "Cited By" links that will list any citing articles that are also in their collections.
