To me, sadhana is a daily spiritual practice allowing time and space for an individual to turn inward.
As Yogi Bhajan (of the Kundalini yoga tradition) says, "Sadhana is self-enrichment. It is not something which is done to please somebody or to gain something. Sadhana is a personal process in which you bring out your best."
Sadhana could be taking a walk in nature, doing breath work or yoga asanas on a mat, spending time meditating or chanting, reading and reflecting on a poem, or simply watching the sun rise.
Please accept this post as a possible starting point for your own practice today, including a story told by Soren Gordhamer about his work with an incarcerated man, found in an essay by Maia Duerr:
A guy named Michael was in for a gang-related murder and used to come to the classes. But during the yoga, he would never really do the yoga very much. During the meditation, he would just kind of look around. He wasn’t very involved. But afterwards he gave me a big hug and always thanked me. Over the weeks I started to get frustrated with him. Like, ‘Why do you show up to class if you’re not interested in practicing?’ And then one day it hit me: he didn’t come for the meditation or the yoga. He came for the hug....
If you never formally sit and close your eyes and meditate, but [if] you’re creating a space that supports people where compassion can come forward and where they feel accepted, that is actually more the central issue, and really maybe the heart of contemplative practice.