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, journaling or simply watching the sun rise.
Please accept this post as a possible starting point for your own practice today.
Finding my people has been so game-changing for me that now I wonder if that isn't the most important reason why we need to do our work in the world. (Though I know intellectually we will all have our own motivations.) I want people to be brave, I want them to not get trapped on the idea hamster wheel, I want them to put their stake in the ground so their peers can find them. So none of us has to be who we are in the world alone. ... Letting ourselves be seen opens us up to being loved.
— Jen Lee & Tim Manley, The 10 Letters Project: A Year of Art and Friendship