In the present age of Kali yuga mantra japa is the yuga dharma, or main process for self realization. It is simple, requires no background qualification, and can be done anywhere at any time.
Sit down in a peaceful place and silently chant your mantra. In the beginning start for 10 minutes, and gradually increase. The mind will become fixed and peaceful usually after 30 minutes, and then the more fruitful sadhana will start.
Other options for sadhana are puja (worshipping a deity of God), meditation (dhyanam), svadhyaya (self study of scriptures), etc.
