“ Content with whatever gain comes of its own accord, and free from envy, the wise are beyond the dualities of life. Being equipoised in success and failure, they are not bound by their actions ”
Source: Bhagavad Gita 4:22
Perform all actions forsaking attachment to the fruits of actions, being indifferent to success and failure. Such mental equanimity is called Yoga
A thinker sees his own actions as experiments and questions--as attempts to find out something. Success and failure are for him answers above all.
Do not let arrogance go to your head and despair to your heart; do not let compliments go to your head and criticisms to your heart; do not let success go to your head and failure to your heart.
You should learn to think of one thing at a time with all the power of your mind. Your whole attention should be there. Doing things in a lackadaisical way leads to failure and misery.