"We have to do the best we can. This is our sacred human responsibility." Albert Einstein.
"If a jobs worth doing it's worth doing well", is a phrase I've often repeated to myself and to my daughters.
Dr Jane Goodall also recalls similar words from her childhood, "If you are going to do something, do it as well as you possibly can".
Focus on aspects that are under your direct control, doing what you can to the best of your ability. Accept that other aspects may not go as you wished.
“You have power over your mind - not outside events. Realise this, and you will find strength.” Marcus Aurelius, Meditations.
Doing the best at this moment puts you in the best place for the next moment.