If you’re starting new and would like to do the SEO for your website yourself I would recommend to start with Google’s Keyword Planner. It’s very easy to use and offers insights on the Global keyword volume, keyword volume by country, related keywords and competitiveness of the keywords. Begin your process by brainstorming with your team and jot down the list of keywords which you and your team believe to be the right set of keywords to target. Analyze your set of keywords using Google’s keyword planner and find out the related keywords.
To get a better selection of keywords, you can try Google’s Auto complete option, type the keyword you believe is your target keyword and note down the list of related keywords suggested by Google. Since the search market is dominated by Google it’s better to hear straight from the horse mouth than relying on other tools. . Get all the variations through both the procedure and finalize the final set of keywords.
Though there are other tools like Wordtracker and Semrush but you can begin with Google’s keyword planner. If you’re wondering how to use Google’s Keyword planner, here’s a video for you.