SEO is not about putting in any random keyword on your website and hoping that it would open up a plethora of business leads. Google gets over a billion queries everyday. So in order to be found for keywords which are relevant for your business, a careful and meticulous planning needs to be done.
If you are in the business of selling shoes, you want your website to target keywords such as “buy shoe online”, “best shoes” etc, which are keywords which users will search on Google for the purpose of transaction.