When it comes to Keywords, as a brand or e-commerce website, you should ask yourself the following questions:
WHAT type of keywords do customers type/use when they are searching for something ? How do they type them ? Where do they type them ?
We can use some free tools such as Google Trends and Google Ads Keyword Planner for more insights. There are also many others : Ubbersuggest, Keyword Tool, Soovle, SEMrush (Premium), Wordstream Keyword Tools (premium), MOZ Keyword Difficulty (Premium), etc. Each of them has its own advantages and/or disadvantages. However, choosing one over the other is down to personal preference and previous experience.
Usually, we can have two types of keyword: Short & Long-tail. Long-tail keywords usually represent 80% of all traffics of a Website. They help companies to attract qualified audience (people who are exactly looking for your product/service). In addition, the competition is often low for these keywords and companies will have a better ROI.