In theory, creating a citation alert with Google Scholar is easy. Search for the paper, click on the "Cited by X" link just below the result, scroll down and click on "Create alert", and finally confirm by clicking on "Create alert".
However this works only for articles that already have at least one citation. If an article has never been cited, the "Cited by X" link doesn't show up. This is annoying because as an academic researcher I would like to be alerted when a given article is cited for the first time. Do you know of a way to work around that limitation?