Perform your duty to the best of your ability, even if others around you do not. Ravaṇa did not do his duty but that did not stop Mandodari, his wife, from doing hers.
Although the people of Ayodhya did not appreciate the sacrifice of Ramacandra and Sita, Ramachandra still performed his duty as a king despite their criticism. Mastering one’s personality thus is an achievement greater than any worldly gain.
Determine your duty and hold on to it, like Bhishmacharya, who took a vow to serve and protect the throne of Hastinapura. Bhishmacharya loved Arjuna and his brothers and knew they were in the right, but his vow bound him to protect whoever sat on the throne of Hastinapura and he remained steadfast in that duty. His duty, his dharma, was not to support the forces of evil but to honour his oath. Actually, the other lesson here is to not make vows of that nature, which bind us for the future, regardless of what may transpire. Instead, vow to stand for the truth and the truth alone.