A market  moving by creating higher highs and higher lows is a bullet market, that means its in an uptrend  

 

 

 
the opposite move, where the market is creating lower highs and lower lows, is a bear market or in a downtrend.
I use to enter a market, exactly, when there is a clear signal of a trend end and also the start of a new trend to the opposite direction. Failure of a trend to fill up a swing, is a strong trend change signal and a clever moment to enter the market! For how long will I stay in the maket may calculated using Fibonacci levels.
 
In that example GBPUSD is in a downtrend since April 2015. but on April 2016 a swing did fail to get lower so I consider this could be a signal of a trend change to a bullet market.   

I may enter the market only after the failure is conformed, that will happen only if the market is finally goint to move over the last swing top (green line) only in that exactly moment I am going to enter the market. I give an pending order a buy/stop on 1.46 that means a few higher than the last swing top -I do that for security purpose, to make sure this is really a change trend signal.

I fix the stop/lose order at 1.3835, wich is the lowest level of the last successful downtrend swing. I consider if the market does move lower than the last successful downtrend swing, there is no failure swing and no trend change at all, but this is a personal over risk I want to take, a market also moving lower than the failure swing’s low should consider as not a failure swing at all.
Fibonacci levels do designate the possible exit moments. This could be at 161,8% (1.481) level or at 261.8% (1.532) level or partly at first level (161.8%) and partly at the second level (261.8%). 

Failure Swing by Despotis Avramis