Buying and selling are interrelated to the principle of demand and supply. If more people are buying than selling the price of the asset increases and if more people are selling than buying the price of the asset decreases. Thus the price of the currency continuously changes.
I think that the maximum number of traders who became successful in the financial markets opted for the long term trading. In case of Short Term trading the number of traders loosing are more than the number of traders which are successful.
I think moving averages like SMA and EMA are the simplest and best technical indicators for trend following. I have tested the strategy based on these indicators and found that EMAs crossover is best way to do the trend based trading.
The longer time frames like 1 H or 4H are much more promising in context of the technical analysis when compared to smaller time frames like 5 min or 15 min.
Yes, I think the economic and political news effect the forex market. The various news sentiments have short term as well as long term impact on the forex prices.