If you go to Search Console under the Acquisition tab and then click Queries, you’ll be able to see different searches (aka keywords) that users found you through. You may have to set this up, but it’s easy to do and only takes a few minutes; you can see how here. Use this information to evaluate and monitor your keywords to see what’s working and what needs to be changed.

The objective of keyword research is to generate, with good precision and recall, large number of terms that are highly relevant yet non-obvious to the given input keyword.[2] Process of keyword research involves brainstorming and the use of keyword research tools. To achieve the best SEO results, it is important to optimize a website as well as backlinks for the most relevant keywords. It is good practice to search for related keywords that have low competition and still a high number of searches. This makes it easier to achieve a higher rank in search engines which usually results in higher web traffic. The downside of this practice is that the website is optimized for alternative keywords instead of the main keyword; main keywords might be very difficult to rank for due to high competition.[3] There are three essential concepts to consider when conducting keyword research. Good keywords are closely related to the subject of the website. Most search engines use an internal quality system to check website relevance related to possible keywords, a non relevant keyword is unlikely to rank well for a website.[4] Good Keyword that are highly competitive are less likely to rank in the top. Keywords that have no monthly searches generate no traffic and therefore are useless for SEO. Keyword stuffing in a web page should be avoided.

It would be great if you can provide comparative analysis of this tool with Google Keyword Planner. Since you’re using this tool so you can provide best comparison. One differentiation which I understood is that this tool works for yahoo and bing as well whereas Google keyword planner works only for Google but Google being a dominating search engine, gives the highest returns, so only this reason may not be enough to buy it.