Best Simple Way to Research a Niche?

I'd start by exploring topics you already know or are interested in, then use Google Autocomplete, People Also Ask, and keyword tools to find specific questions with low competition. Check the top 10 search results to see whether they are dominated by large authority sites or whether smaller blogs are ranking too. Choose a niche with enough related topics to publish consistently, and focus on long-tail informational keywords rather than chasing high-volume keywords right away.

i would do a research on google search first, then check keywords with a SEO tool.

Start with Google Autocomplete and Reddit questions, then validate long tail keywords using Ahrefs or Semrush.