The main factor that affects the price is the opinion of the majority. All other analysis types and any thing is related to that. Which means you don't have to be smart but you need to always think like the majority of traders.
However, minority of readers earns money. That's because this majority is always changing and shifting.
There are a list of factors affect the opinion of the majority:
1- fundamental analysis which depends on news and economic calendar.
Economic Calendar: contains all economic reports with its importance and pre-scheduled.
Usual news affecting any country will also affect its currency price.
2- technical analysis which depends on charts, resistance, support, etc...
This is a pure statistical evaluation and I will explain it in coming courses