Bhagavad Gita starts with a verse whose first word is dharma, which means
duty or right action. The concluding verse of the Gita ends with the word
'my'. When these words are taken together they become 'my duty' or 'my
work'. That summarizes the whole teaching of the Gita. It means you should
perform your prescribed duty to the very limits of the human capacity for
excellence and perfection, doing the work that is appropriate to your stage
When you are a student study your lessons well. When you are a householder perform your work and family responsibilities properly. When you are retired perform the duties appropriate to that stage, and if you have renounced the world to engage yourself in contemplation of the reality, then stick to that path. When you follow your prescribed duty in the very best way possible, discharging your duty sincerely and conscientiously, then there will be no confusion or misery.