Any economy needs industries to survive. An industry is the production of goods and services within an economy. There are many types of industry. There are those that deal with collecting and producing raw resources such as lumber or metals, there are those that manufacture those raw materials into new products, there are those that provide services such as selling products and providing transportation, and there are those that don’t fit cleanly into any of those other groups such as tourism.
Which industries do the economies in your world rely on? The geography and traditions of the countries in your world will influence which industries they depend upon. A coastal country with a lot of rivers will rely more on fishing than anything else. A mountainous country may not be able to rely on other industries such as lumber or farming, and will instead rely on mining and quarrying stone. The main industry also influences the traditions and culture of people within the country.