Naam Sumiran (continuous chanting of God’s name) is the best way to develop unconditional love towards God. It purifies the heart very fast. A person with pure heart can progress quickly in meditation. In my opinion Kriya Yoga and Japa Yoga should be practiced together. Practice Kriya as per your schedule and then choose any name of God and try to chant it in your mind continuously all the time. You will surely progress fast towards Divinity.
अगुन सगुन बिच नाम सुसाखी | उभय प्रबोधक चतुर दुभाषी ||
Aguna saguna bich naam susakhi | ubhay prabodhak chatur dubhsi ||
Between the unqualified Absolute and qualified Divinity, the Name is a good intermediary. It is a clever interpreter revealing the truth of both.
सगुनही अगुनही नहीं कछु भेदा | गावत मुनि पुराण बुध बेदा ||
अगुन अरूप अलख अज जोई | भगत प्रेम बस सगुन सो होही ||
Sagunahi agunhi nahi kachhu bheda | gavat muni puran budh veda ||
Agun arup alakh aj joi | bhagat prem bas sagun so hohi ||
There is no difference between qualified Divinity and the unqualified Brahman: so declare the sages and men of wisdom, the Vedas and the Puranas. That which is attributeless and formless, imperceptible and unborn, becomes qualified under the influence of the devotee’s unconditional love.