Aditya,
Since you have stressed the point Psychology I would say I follow what Lord Krishna said in Gita,
"Sukhe Dukhe same Kritva Labha Alabav jayav ajayav"
Means accept "happiness, sorrow,profit,loss and win and defeats with equal mind".
I never get excited by big profits nor get deterred by series of losses if they happen.
Both in life and trading, I have seen both parts.Hence I learn't accepting both of them heart fully.