More and more databases offer scholarly authors the ability to track citations to their own works and others as well. The tools mentioned on this page are just some of the ones available. In general, look for "Cited by" when doing a search for an item in a database.
Various databases can have greatly differing citation practices, so it's important to place the number of citations an item has received in context with other items in the same discipline.
You can use Google Scholar to both see all the articles that have cited an item you're interested in, as well create an alert for any new citations.
To see all current citations, search Google Scholar for the item you're interested in. Once you see the listing for that item, click on "Cited by XX" to see all the items that have cited it. Once you've clicked that, you can then click "Create alert" to receive an email ever time Google Scholar finds a new item that cites your article.
Many studies have found that Google Scholar collects the most citations to scholarly articles, books, and other items. However, it has been shown to count duplicate citations and citations from sources that aren't scholarly in nature, so you might want to verify that the total number of citations is accurate.
If you have a Google Scholar profile, you can also create an alert any time any of your works receive a new citation. In your profile page, click on "Follow" or "Following" and select "New citations to my articles" in the pop up box. Enter the email address where you want to receive citations.
You can use Web of Science to track new citations as well, but note that Web of Science will only track citations from other journals and outlets included in Web of Science. This means you will generally see fewer citations for items in Web of Science compared to Google Scholar. \
First search for the article or other item you want to see citations for and then click on its title to view the record for it. It will then show you "X citations." You can click on the number of citations to view the specific items. To create an alert, click on "Create citation alert" within the record for the item. You will need to be signed in to a Web of Science account to create the alert.
Library Search will also sometimes track citations to an article or other scholarly material, but not always. When you run a search in Library Search, look for a double-headed red arrow pointing up that's labeled "Find sources citing this" when you hold your mouse over it. Clicking on this will bring up the individual citing items.