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.
I was fascinated by what I couldn't see but would die without. All About Air was the book I repeatedly checked out of the library. Four gases create air: nitrogen (78.09 percent), oxygen (20.95 percent), argon (0.93 percent), and carbon dioxide (0.039 percent). Water vapor (2 percent) is also found in the atmosphere. This gave me confidence. The unseen world was real.
I would lie in a sun puddle on our living-room floor, staring at dust particles dancing in the column of light streaming above me. Using my field guide to air, I tried to differentiate flakes of dried skin from specks of dirt, sand, or salt from the sea. Smoke and pollen were in this mix, and I imagined dust mites eating the microscopic flecks floating in the air, swirling around us all the time, too tiny to see. The sun became an honest broker in showing me what we breathe. But what thrilled me most was the fact that millions of meteors burn up every day as they enter our atmosphere. As a result, Earth receives ten tons of dust from outer space. Not only do we take in the world with each breath, we are inhaling the universe. We are made of stardust.