Classic price pattern
The 'head and shoulders' formation highlighted below gave a clear indication that trader sentiment had shifted from bullish to bearish.
By spotting the formation - and what it revealed about the shift in overall market psychology - you would have been able to maximize your profits by closing out any long positions in EUR/USD currency pair - or, opening a short position - before the downward move began in earnest.
So, did you identify it correctly?
If you did, great job - it will only get easier with experience.
If not, don't worry - you'll get the hang of it with a bit of practice.