Subscribe to their newsletters and see if they mention anyone. Email the competitor and ask if they have case studies. They usually do and if they don't they w

Subscribe to their newsletters and see if they mention anyone. Email the competitor and ask if they have case studies. They usually do and if they don't they will scramble and provide one. Use a search engine and do some deep searches. Search on social networks. See who liked their content/page. Set up a google alert. These are just a few...