Within the context of Hinduism, how would one break a curse?
Keeping various Hindu Stories in mind the Curse or Boon once given can not be broken (because of respect towards the person who has given the boon/curse),
it has to take place in some form but if the person who is cursed realizes his mistake, or the Curse was given out of mistake there is always a soft way or the curse can be taken in your favorable way.
However also we consider that every major thing is in God's Maya (master plan), so you may see many curses internally relates them with other curse or helps them in fulling them , Like jaya and vijaya were to be killed by avatar of Lord Vishnu and all the curse that Ravana has been given accelerates that situation.
Like sage Bhrigu has given curse to vishnu (matsya purana) that he has to take birth at earth , this curse is one of most important for the birth of all earthly avatars of God.
Almost every story relates with some or the other curse, may it be jaya/vijaya ,ahalya etc, and all these curses/boons promotes the God's plan.
Like for Jaya Vijaya God says the curse was in his plan
O brāhmaṇas, know that the punishment you inflicted on them was originally ordained by Me -SB 3.16.26
Although God can Nullify the cause of that curse as he says here
Though I am capable of nullifying the brāhmaṇas’ curse, I would not do so. On the contrary, it has My approval. SB 3.16.29
Shri SitaRama also Killed bali from back side and killed ravana in human form being the incarnation of Supreme Lord himself , because he has to respect all the boon/Curses which were given to them.