When you are chanting "Hare Krishna" the body may be breaking, the mind may be reeling but you should know for sure that the soul is in 'ecstacy'.
The quality of chanting dpends on purity. Purity is dependent upon surrender. Chanting and Surrender happen simultaneously.
When one’s heart is purified by the association of devotees and by the avoidance of the offenses committed while chanting and worshiping the Lord, the transcendental name, form and activities of the Lord are revealed by the Lord.
When love increases for the holy name of Lord Krishna, then automatically our hesitation for chanting and dancing ends. As chanting the holy name and dancing on the holy name are not different from Krishna.
We must become strongly established in the holy name. Naam Sankirtana is the only thing which goes back with us and it is possible till the end of our last breath.
The Perfect spiritual practice for this age is to chant the holy name with full conviction and to make others also chant the holy names of the lord.