Using economic calendar is very important thing when you are opening trading positions.
Economic calendar gives us the schedule of economic new that will be published at certain time and will affect the market and the price movement.
Most common mistake that beginner trader usually makes is ignoring economic news, for example looking at just technical analysis, there might be perfect entry point on the market, but also there might be news scheduled in 5 minutes, this news is lets say 50/50 it might be positive or negative so success of your order just depends on pure luck.
Some strong economical news might move the market 200+ pips which is very, very huge movement. check economic Calendar every morning before you open trade and avoid trading on assets which has strong news coming out that day.