One of the best lessons I took away from my schooling was the habit of checking sources. I had an instructor who must have spent an enormous amount of time doing this. She always demanded quality sources and I've come to expect the same.
We need more like her in academia these days. It seems the peer review system, coupled by the always present push to publish, has seen some spectacular failures of late. The reader must always be aware and do their best to verify information.
Some good pages to watch for retracted studies are: The Scientist and Retraction Watch
I would also recommend visiting sites somewhat regularly to see if retractions are posted there. These seldom make it to the same news sites that cite them. Such is the risk we all run in this information age.
Please feel free to leave a comment with any other suggested sites.