Forex traders essentially pursue the profits that can be made by buying and selling currencies following increases or decreases in exchange rates. Exchange rates change over time, whether on an hourly, daily, weekly or longer time frame basis. Publicly available information is the main factor affecting exchange rates, meaning in principle that anyone with ready access to world news can become a forex trader.
Fundamental (i.e. public information) factors affecting Forex include global and national political events, monetary flows, central bank decision making (mostly on interest rates) and the global and national economies.
Political news such as national elections, the fall of a government, international regulations coming into effect or war can have dramatic effects on currencies. This is not restricted to the currency of the market in which such events take place, due to the interconnectedness of the global economy.
Monetary flows monitored by Forex traders are typically generated by international trading. The buying and selling of goods across borders tends to strengthen the currency of the market receiving the demand. Nations with large scale trade deficits (where the volume of imports is larger than that of exports) tend to have a depreciated currency.
High interest rates set by central banks typically have the effect of strengthening the currency of the national economy the bank helps to regulate. The macro economy and national economies, finally, can increase or decrease exchange rates. Economic indicators include GDP, unemployment numbers, consumer behaviour and the housing market.