Keyword research is the first step you should follow before writing any content. For that, you can follow these strategies for keyword research.
For example, I want to write about Goa places then you can search keyword shitter and type your keyword. It will show you all the keywords that people search
Then go on ubersuggest and find out their search volume and pick keywords depending on search volume and difficulty
Do not add more than 1% keyword density or use alternative words
Hope this helps
For more complete knowledge about seo read these articles