Too many lessons in this chapter, but I'd want to consider vs 45
A good man brings good things out of the good stored up in his heart, and an evil man brings evil things out of the evil stored up in his heart. For the mouth speaks what the heart is full of.
You cannot produce what you haven't stored up, so a man's output(character) is traceable to his input.
There is a saying..
Thoughts becomes words
Words become actions
Actions becomes habits
Habits becomes character
So if want to change a character(output) of our person, we need to start from our thoughts.
Proverbs. 4:23 buttresses my point
Keep your heart with all diligence, For out of it spring the issues of life.
Also Proverbs. 23:7 simplifies it
as a man thinks, so is he
So we have to start checking what fills our thoughts and this can be done by studying and internalizing God's word through meditation. So the more I study and do God's word, the more like God I become and hence my output or outlook or character is changed.
So,