I'm trying to find other articles that have cited an article I already have. My professor calls this "forward searching." How can I do this?

Google Scholar is a great tool for this kind of search.

After searching and locating your article in Google Scholar, take a look at the links beneath the abstract. You may sometimes seen a link that says "Cited by" followed by a number.

Clicking on this link will give you a list of other articles that have cited the original article.