Like many, you probably use Google Keyword Planner Tool to find keywords to target on your website and in your content. But guess what? You can also use it to spy on your competition. Not only is the Google Keyword Planner tool easy to use, but it’s also free. This is probably the best place to start.
Once you log in, take these steps:
Select “search for new keywords using a phrase, website, or category.”
Enter your competitor’s URL and click “get ideas.”