People living in Ancient Greece had to sail or travel over mountains to get from place to place. This is because mountains mostly covered the land and it was nearly impossible to travel anywhere on foot.
Farming was also a difficult task because the land here was very steep. Another thing was that with the limited flat land, settlements usually fought over land. With that amount of limited space they had to build earth steps to make the land flat.
As population increased, their wasn't enough cropland to feed everyone in the community. Thus resulted in people having to make colonies to bring back food from other islands. These colonies helped spread Greek culture.
Goods were usually carried on ships owned by merchants who traded with other colonies. Navigating these ships were difficult because there were no such thing as lighthouses back then, stars were the best thing that they had back ten for sense of direction. Olive oil and pottery were traded from the mainland were traded for other goods such as grains, timber, and metal.