Sadhana is a Sanskrit term meaning "practice." To the sadhu or yogi, the way you integrate yoga into your life will vary based on your level of maturity in the practice, your own personal discipline (abhyasa), commitment and, according to yogic philosophy, your karma in this lifetime. What sadhana is not, is comparing and judging your practice against another's. Sri K. Pattabhi Jois is known for saying, "Practice and all is coming." (Read more about Pattabhi Jois in The Founder of Ashtanga Yoga.)
To evolve your sadhana, dedicate what you can to your daily practice because consistency is the key to forming the right habits to achieve the best results. It is better to be in sadhana just a little bit every day rather than one full day a week. This may be 15 minutes at sunrise, simply breathing and practicing mindfulness meditation, or it could be taking a daily yoga class.
There are many ways to integrate yoga into your life. Yogis who adhere to the eight-limbed path of the Yoga Sutras know that asana is just one of those ways. Practicing physical yoga asanas will help the body begin to move stagnant energy and bring both awareness and healing to your body, which aids the mind and spirit. (Learn more about The 8 Limbs of Yoga.)
For most of us in the West, our practice starts with taking a few asana classes. Immediately we begin to feel changes in our bodies. From there we tend to explore seated practice, perhaps changing our diet, reflecting on our personal relationships, or forming new friends in our yoga kula.
The goal is that we experience steady progress, both inwardly and outwardly. The key to seeing development in your sadhana is vairagya, which translates to non-attachment to outcome. Yoga practice is about personal mastery, not personal perfection. It is about the journey, and not the destination. (Read on in The Wisdom of Non-Attachment.)