Let's say you find a relevant article, but it's too old for your paper. One way to look for newer research is to use some of the ERIC descriptors assigned to the older article. Another way it to see who has cited the older article. Google Scholar lets you do this easily. Search for your older article and then look at the Cited By link.
Citations can be strong or weak. If a newer article is about research that directly flows out of an older study, the citation that leads you to the newer article can be quite strong and useful. But if the newer article cites the older one just because it was written by someone influential in the field, it's a weak citation and may be a less than ideal use of your time.