Some situations we respond to by instinct and others we respond to by habit, like Pavlov's dog. We have free will. However, our will gets all but nailed to the floor by habit. An essential part, then, of exercising free will is to choose which habits we will form and which we will uproot.
I first encountered this idea while reading Charlotte Mason on childhood education. Well, no, it's inception for me was in C.S. Lewis' Mere Christianity, book IV, chapter 7, "Let's Pretend".
"When you are not feeling particularly friendly
but know you ought to be, the best thing you can do,
very often, is to put on a friendly manner and behave
as if you were a nicer person than you actually are.
And in a few minutes,as we have all noticed,
you will be really feeling friendlier than you were.
Very often the only way to get a quality in reality
is to start behaving as if you had it already.
That is why children's games are so important. They
are always pretending to be grown-ups -playing soldiers,
playing shop. But all the time, they are hardening
their muscles and sharpening their wits so that the pretence
of being grown-up helps them to grow up in earnest."
I'm sure I could credit many authors with contributing to the pot of this idea, as it stewed in my mind. But back to Charlotte Mason. She was a late 19th/early 20th century educator who is rightfully being saved from obscurity, mainly by home-schooling parents. In her book, Home Education, she writes,
"One of the great functions of the educator is to secure that actions will be so regularly, purposefully and methodically sown that the child will reap the habits of the good life, in thinking and doing, with a minimum of conscious effort."
Ms. Mason goes on to identify the most important of these habits, including the "habit of attention", the "habit of manners", the "habit of truthfulness", the "habit of gratitude", among many others. Children will leave home and develop their own philosophy of life, of course. But if a boy has been trained to the "habit of manners", chances are that he will be polite. If he has practiced the "habit of truthfulness" for many years, most likely he will be an honest man. Again, from Home Education,
"Educate the child in right habits and the man's life will run in them, without the constant wear and tear of moral effort of decision."
This is very important. As I wrote in my previous post, I have few good habits, that I can think of , which means that I am at a severe disadvantage as regards doing good. Good acts that I can choose come with tremendous, often dissuading, "wear and tear of moral effort". It is incomparably harder to develop habits in an adult than in a child but I owe it to myself at least to try. Here's a saying attributed to Thomas a Kempis:
Sow a habit, reap a character,
sow a character, reap a destiny."