Premanand Maharaj Ji
How do I build self-discipline?
Bring the mind back, again and again
When Arjun said the mind is restless, Bhagwan told him abhyas (repeated practice) and vairagya (taking the mind away from the whole world). Through abhyas we can bring the mind under our control.
Bhagwan himself said in the Gita: through the yoga of abhyas (repeated practice), bring yourself to a state where your chitta goes nowhere else.