Chapter 2 · The Yoga of Knowledge · Krishna said
Bhagavad Gita 2.48 — Evenness is yoga
योगस्थः कुरु कर्माणि सङ्गं त्यक्त्वा धनञ्जय। सिद्ध्यसिद्ध्योः समो भूत्वा समत्वं योग उच्यते ॥
yogasthaḥ kuru karmāṇi saṅgaṃ tyaktvā dhanañjaya | siddhyasiddhyoḥ samo bhūtvā samatvaṃ yoga ucyate ||
Meaning
Steady in yoga, do your work, Arjuna, giving up attachment and staying even-minded in success and failure. This evenness of mind is called yoga.
In today's life
Do your work with full attention, and let success or failure not swing your mood up and down.