Their unique ability makes their Influence with city-states degrade more slowly and recover faster. The Greeks excel at diplomacy and influencing city-states. And of course, develop the Exploration tree to maximize your maritime infrastructure. Look for every opportunity to enter naval combat, both to gain XP and new units. If you start building up your fleet early (by fighting Barbarians, for example), you will have an impressive number of ships that come to the Renaissance Era, which you can use to start conquering other coastal nations. They can convert defeated enemy ships to their side, which allows them to expand their naval power very quickly. Their unique ability is a bit similar to that of the Germans, but oriented towards naval units - they pay less for their maintenance. The Ottomans are a seafaring nation designed for a domination victory.
