What are long-tail keywords?
A technique when creating keywords to target highly specific niche search terms that generally have 3+ words and are easier to rank due to low competition.
You can do this on your own by thinking of the way people actually search. For instance instead of trying to rank for "graphic design", you would want to try and rank for "graphic design in Muskoka". This is just a very basic example.
Use the data visualizer on the right hand side of the page to look at the long-tail keywords that you have decided you want to rank for. There you will see Keyword SEO Difficulty, Monthly Search Volumes, and the Google rankings for that keyword along with tons of other data. I recommend that you do a competitor analysis available in my SEO section at this point. A lot of the data you need is available in this view as well, which will save you some time.