Karma yoga is described as a way of acting, thinking and willing by which one orients oneself toward realization by acting in accordance with one's duty (dharma) without consideration of personal self-centered desires, likes or dislikes. One acts without being attached to the fruits of one's deeds.
In the Bhagavad Gita, Krishna says:
Therefore, without being attached to the fruits of activities, one should act as a matter of duty, for by working without attachment one attains the Supreme.
Krishna then goes on to describe how Arjuna should surrender the fruits of his actions (good or bad) to him, Krishna, (as the Supreme Person or avatara):
Therefore, O Arjuna, surrendering all your works unto Me, with full knowledge of Me, without desires for profit, with no claims to proprietorship, and free from lethargy, fight.
Krishna explains that work done without expectations, motives, or anticipation of its outcome purifies one's mind and gradually makes an individual fit to see the value of reason. He states that it is not necessary to remain in external solitude, or remain actionless, in order to practice a spiritual life, since the state of action or inaction is primarily determined in the mind.
In order to achieve perfection of life, Krishna explains that it is important to control all mental desires and tendencies to enjoy pleasures of the senses. The practice of karma yoga in daily life makes an individual fit through action, meditation and devotion to sharpen his reasoning, develop the intuitive power of acquiring knowledge, and to transcend the mind itself.