How to search for hidden keywords?

Finding keywords is the most important part in blogging and SEO. If you track down the right keyword then the seo becomes so easy but if you stuck on Hard keywords than it takes lot of time for reach the tp google position. i use Seo tools like semrush and ahref and sometimes manul google search to research for keywords. What are your methods for this?

Stop focusing on researching/finding keywords to build content around and, instead, focus on researching/finding topics to build content around.

What @Roger Marquez said but also once you've got topics and keywords, map them out on a customer journey funnel, read more on the topic here: https://moz.com/blog/customer-journey-mapping-on-google