How much is a keyword worth to your website? If you own an online shoe store, do you make more sales from visitors searching for "brown shoes" or "black boots"? The keywords visitors type into search engines are often available to webmasters, and keyword research tools allow us to find this information. However, those tools cannot show us directly how valuable it is to receive traffic from those searches. To understand the value of a keyword, we need to understand our own websites, make some hypotheses, test, and repeat—the classic web marketing formula.
If you don't know the difference between head terms and long-tail keywords, let me explain. Head terms are keywords phrases that are generally shorter and more generic -- they're typically just one to three words in length, depending on who you talk to. Long-tail keywords, on the other hand, are longer keyword phrases usually containing three or more words.

What I really like about them is extensive detail including the keyword difficulty. Ahrefs uses clickstream data to also show how many clicks you will get from the search engine. This is very useful after knowledge graph integration, as many keywords may have huge traffic but they hardly get any clicks from the search engine. Reason being, they get answers directly from the Google search result. Example of one such query is: “birthdate of any celebrity”
Well, if you haven’t heard the news yet, the word on the street is Google has shut down their widely popular keyword tool for public use. Now if you want access to Google sanctioned keyword data you have to sign up for an Adwords account. Of course there are a ton of theories surrounding why Google would make this decision, some are more obvious than others. But to many of us Google’s motivations seem pointless when we still have work to do! Luckly we exist in a vibrant industry where innovation is at the core of most of what we do. As such we have a slew of different tools available to replace Google’s tool.
The keywords you want to focus your SEO on should closely resemble the vocabulary of your audience. In order to come up with the proper keywords you really have to get inside the heads of the people who search for your website. What terms will people use? How do people search? Which question does your website answer? You should create a list of all search terms people could use and think of combinations and nuances within these search terms.
Long Tail Pro is a keyword research tool that helps you quickly find low competition keywords for your website.  In particular, the tool is built for people doing SEO (search engine optimization) as opposed to people doing paid ads (Google Adwords PPC).  I'm sure there are some advertisers that use the tool for paid ad keyword research, but the tool was built for SEO keyword research.