People show the stuff they’re made of when they’re put under stress. Sometimes they rise to the occasion and become heroic. Other times they run. Part of why war stories are so compelling is because soldiers face the ultimate stressful situation. They’re putting their lives on the line. Your character doesn’t need to face death, but he should have to deal with pressure.
Consider Bailiey, for example. He likes to play golf, but he’s not that good at it. Then he meets a woman who happens to be a very good golfer. He begins to care a little more about his game. Then the woman’s father invites them along on a golfing vacation. Now our friend begins to care even more, because he doesn’t want to look like a fool. Then it turns out that the father has been advising his daughter to break up with Bailey because he doesn’t consider him manly enough. Now Bailey cares even more. He’s going to beat this man if it’s the last thing he does. Then, on vacation, they run into the daughter’s old boyfriend, who just won a golfing tournament.
I could go on and on, but the point is that each twist of the wheel puts this poor man under more stress and pressure. His actions are going to have more significant consequences if someone he loves is involved. His choices will be harder to make. The reader’s going to care about him more, because we know how hard he’s struggling. As a writer, I’m going to have an easier time writing a story when the stakes are higher. Is he going to crack! Or is he going to reach inside himself and fine some strength of character he didn’t know he had?
In order to put your characters under pressure, you have to know them well. This is why fleshing our character is so important. For this story, I would want to know how Bailey learned to golf, how he met this woman, what sort of romantic history he has, where he works, what he looks like, how much confidence he has, how he dresses and why on earth his parents decided to name him Bailey. The more I know about him, the more fully I can make him come alive. What if, in thinking about Bailey’s character, I realize that he was captain of his high school football team? Does that change things? I think so. Explore your characters. Get to know them. Make them suffer.