How to control your emotions during corrections

I try not to be influenced by emotions when buying shares. To prevent this I order a predetermined buypoint.
For example, according to my own calculations Amazon is still undervalued.
My next buypoint is 2900 because on the weekly chart the 20EMA can serve as support.
If the price drops to my buy point, I will buy it automatically.
Then I will set a new and lower buypoint order.
Problem solved!