Your hero is a hurdler, so make sure you put up some hurdles.
You hear me banging on a lot about figuring out what it is your character WANTS and NEEDS, and how isolating that one desire can motivate your entire story. I tend to gloss over the other important part of the equation though. To get what she wants, your protagonist must overcome some obstacles.
Put things in her way, make her scramble and cut her knees up as she clambers over them. And then, when she’s on the other side, put another, much bigger one in front of her. The more she cares, the more we like her.
A well-drawn antagonist is a good moving hurdle too. Someone who wants to stop her from getting what she wants as much as she wants it.
But something else worth trying is to make the solution to one problem the catalyst for the next problem. (In the same way you structure a good action scene). When Luke Skywalker rescues Princess Leia, it unleashes the Storm-Troopers running from which brings them to a huge cavern which needs crossing.
Ah but, you cry, I’m not writing an action adventure, mine is a story of lost love and adolescent experimentation.
So what? The principle remains the same. If your hero’s lost love is at the other end of the race track, it’s pretty boring to see him running towards her without jumping over any of those hurdles. Maybe there’s a jealous ex, or a protective brother in the way. And by foiling the ex, he shows a side of himself that repulses her. How’s he going to swing across that cavern?