(1) Resentment is futile, even if our critical assessment is correct, as it changes nothing, so stop defending it. If action is necessary, take it. But you do not need to be resentful to do so.
(2) To be resentful is to focus perversely on what is wrong rather than what is right. Focus on what is right. This means the deliberate fostering of gratitude.
(3) Forgive. This means (a) stop taking the universe personally: nothing is about you, even if it seems to be about you (b) recognise that everyone and everything has the right to be defective: you won't be comfortable unless you accept this (c) foster acceptance and love for the person, institution, or situation by refusing to engage in attack thoughts and by surrounding it, in your mind, with blessing.
(4) Trust God that there are sufficient resources available in the universe to be OK even if things don't go your way.
(5) Seek God's will in making the most out of your contribution to the day.
(6) Finally, regarding the object of the resentment: do not think about it and do not talk about it. If you inadvertently think about it, bless it and return to your day.