If you want to pay, Google Ads is a quick fix (but not a long term solution).
This free tool helps you determine which keywords to go for, and is actually of some help when cheapening out and doing it organically:
https://adwords.google.com/select/KeywordToolExternal
However, to organically improve your search engine ranking, you need to develop keywords, metatags, alt tags and page descriptions relevant to your audience (and expertly copywrite them within your text so that it does not ruin your user experience).
Contrary to popular belief, finding the best keywords is not always as easy as it sounds, because the best terms (KEI) are defined as a ratio between 'most searched' vs 'least returned results' - kind of obvious really. Therefore, say you're a car mechanic, subjectively asserting that 'car fixed' is a good term could be totally wrong, either because people are not searching for this term or because it returns too many results. Often, when proper research is done, the best terms can be something totally surprising and not what you would have thought of.
So where does this leave us when trying to avoid paying for SEO? Fortunately, for Cyprus businesses, the simple modification of adding Cyprus, or one of it's towns, can bring you right up to the top of SE rankings. This is simply because the level of competition is low online, where companies are far behind their European counterparts when it comes to having an internet presence. People tend to modify their Google searches by putting, for example, 'car mechanics Cyprus' or 'Car mechanic Larnaca', because to not do so will return international (usually UK or US) results. I know plenty of SEO companies in Cyprus who, frankly, don't know the above and will willing cheat you out of your money simply for doing the above that you can do for free.