How do you do keyword research?

Keyword is very important and the way forward before you write your first word.
What is your favourite way to do keyword research?

I'll start:
1. I find weak websites.
2. Using ahrefs, semrush, moz, etc, I find the keywords they rank for. You can easily use moz for free for this part.
3. Write better articles for those keywords.
4. Rank and bank.