The definition of success is as old as mankind— from being the best hunter to being the best warrior to being the best businessman. Currently in modern culture the prevailing model of success is very Piscean and defined as economic. If you make a lot of money or have a lot of possessions, you are considered to be successful.
To a spiritual person success comes from having the endurance to maintain the discipline to connect with the Infinite every day, to allow the tools that we have been given to permeate the fabric of our daily lives, to bring the heavens to the earth and the earth to the heavens. Life stems from the One, the Infinite, Ek Ong Kar. It manifests on the physical plane for a finite period of time and then returns back to God. Our teacher, the Siri Singh Sahib (Yogi Bhajan,) reminds us of this fact, re-orienting us to remember that we are spiritual beings having an earthly experience and not earthly beings having a spiritual experience. This reminder is crucial in helping us to define success.
As spiritual beings in the land of maya it is important to maintain our focus. The time here on earth is short, as the Siri Singh Sahib (Yogi Bhajan) has said, “All things come from God, and all things return to God.” It is easy to lose our focus and to be caught up in the physical plane. That is why our teacher has given us so many tools to help maintain our focus on the Infinite, and reminds us of universal truths like giving 1/10th of our day back to God as Sadhana and 1/10th of our income back to the Infinite as Dasvandh (tithing).
Along with these tools he has given us yogic tools to support our physical body, like cold showers, yoga, an understanding of foods and diets to achieve certain goals. And tools to support other aspects of our being like meditation, Solstices, and White Tantric. These tools give us the capacity to maintain our physical body at the original operating instructions and to stay focused on our spiritual connection to the Infinite.