Keyword research is one of the most important, valuable, and high return activities in the search marketing field. Ranking for the right keywords can make or break your website. Free Keyword Research Tools:

https://keywordtool.io/
https://adwords.google.com/KeywordPlanner

Google Autocomplete
https://ubersuggest.io/
https://www.wordstream.com/keywords?dt=1
http://membership.keywordeye.com/
https://www.keywordrevealer.com/

See keywords of competitors:
https://www.semrush.com/

Add also TXT record from google to your DNS settings and check search analysis via:

https://www.google.com/webmasters/tools/