Choosing the right tool for your keyword research is very important, because all the tools are quite similar with small changes.
Knowing about which keywords to choose, which are most helpful in driving traffic to your website, checking out your competitors websites for keywords for which they are ranking on top and making use of those keywords in your website.
Using your competitors keywords and doing some research on those keywords, which will give you more confidence in adding more keywords to your list.
While doing keyword research make use of LSI technique, which is a great way in performing keyword research as well as optimizing your content with keywords.
Because using LSI sends the target to Google on which type of keywords your using in the website and what is the correct meaning for that keyword using latent semantic indexing technique, it will give the right answers to the queries who are searching.
Using long-tail keywords gives your users to get their solutions for their queries because we are using a normal language how user searches for, this will give extra boost in traffic as well as rankings.
Google recently updated Rankbrain algorithm which speaks about the searchers made by the users will be filtered accordingly to the exact meaning of the search made.
So use only those keywords which are relevant to your website services and products, If you use keywords which are not relevant to your services then google will move out those queries.
