As a forex trader i understand how import is the timeframes in forex online trading. I think traders can be right about a potential market movement but be too early or too late when you enter the trade. Timing considerations are twofold, an expected market figure like CPI, retail sales or a federal reserve decision can consolidate a movement that's already underway. Timing your move means knowing what's expected and taking into account all considerations before trading. Technical analysis can help you identify when and at what price a move may occur.
 
I also believe smart traders Always Trade During the Highest Trading Hours. By this I mean when the market is most active whatever the currency pair. This is when the market is most stable and is not subject to a big Banks interference which is totally unpredictable.

These are some forex timing guidelines which can help you to decide which currency pairs you should trade and when:

Euro Session
London session opens daily at 8:00 GMT also 3:00 EST and closes at 17:00 GMT and 12:00 EST. London is one of the largest shopping centers in the world and has a market share of 30% minimum.
Some of the most active pairs during this session include USD/CHF, USD/CAD and EUR/USD.

New York Session / American Session
This session opens daily at 13:00 GMT also 8:00 EST and closes at 22:00 GMT also 17:00 EST. The hot time in this session is usually when the euro traders are still active. Which is between 13:00 and 17:00 GMT also 8:00 EST and 12:00 EST. The most liquid pairs during this session would include USD/CHF, GBP/USD, USD/CAD and EUR/USD.

Asian Session
Tokyo starts off the morning @ 12:00 GMT also 19:00 EST and ends at 21:00 GMT also 04:00 EST Usually currency pairs with the GBP are the most active during this time. EG: GBP/JPY, GBP/CHF. The rates of USD/JPY, AUD/USD, NZD/USD pairs and there crosses are also quite lively during this session.

Hope you are happy and satisfied with my answer.