Chanting of the Hare Krishna maha-mantra is potent always, but it is especially potent in this age of Kali. Therefore Sukadeva Gosvami, while instructing Maharaja Parikshit, stressed this chanting of the Hare Krishna mantra.
"My dear King, although Kali-yuga is full of faults, there is still one good quality about this age. It is that simply by chanting the Hare Krishna maha-mantra, one can become free from material bondage and be promoted to the transcendental kingdom." (SB 12.3.51). This is stated in the Bhagavad gita in the sixth chapter, that one has to control the mind otherwise the mind will become his worst enemy.
The best way to control the mind is to hearing and chanting Hare Krishna Maha Mantra.
Hare Krishna Hare Krishna Krishna Krishna Hare Hare
Hare Rama Hare Rama Rama Rama Hare Hare
Somehow or other fix your mind on Krishna then you will experience peace of mind and your mind will be your best friend.