While it is true that pretty much everybody uses a search engine nowadays, there is an oversimplified idea that if your business pops up at the top of a search page, people will flock to your site and business will boom. Being top of a Google search isn't necessarily what you should be aiming for.
Start with asking yourself questions about your marketplace: what do I offer? Who am I benefitting? If you want to be effective, you need a good marketing plan that considers these things. Use of search is just one tool to help your strategy.
Rather than a major focus on keywords, which may be a very niche subject in a very broad term, make sure your site's content informs and demonstrates what do you well and, in doing so, you give yourself an organically successful SEO method.