You’ve probably heard of this tool, but may not know how beneficial it is. The cost is very low if you’re running any sort of volume through your advertising account or even through SEO. Try SEMRush Free!
With a high accuracy, SEMRush tells you the keywords your competitor is bidding on, where they get their website traffic, and where your own pages are ranking and for what keywords.
They aren’t always accurate on the CPC of those keywords or the search volume for those keywords, but nonetheless are invaluable for knowing what your competitor’s “pie” looks like and where there are giant holes in your marketing plan.
This is fantastic for paid search and for SEO, and one of my favorite things you can do with them is find out what content to cover next by seeing what long-tail or short-tail keywords all of your competitors rank for.