If you don't understand this reference, don't hold the "reel" button. Just tap it repeatedly until the bar is where you want it.
This. Basically, if you hold the button, it'll go up slower at first but then shoot up. Similarly, when you let go it'll go down slower at first and then fall quickly. But if you just tap it, it'll just go up a little, and then fall a little in between taps. If you find the right rhythm, these will balance out and keep the bar in the same place. Then you can tap a little slower or faster to go up or down in a more controlled manner. Definitely takes some practice but eventually it'll become muscle memory. I agree with the recommendation of buying a training rod for the first few levels.
For some of the harder fish it can be useful to hold the button or let go of it for longer periods of time. Also, if the bar is falling quickly, you can click right before it reaches the bottom to stop the momentum and prevent it from bouncing. But that's trickier and you should probably learn the right tapping rhythm first.
If you're still in spring, most of the fish are relatively easy. The town river has only smallmouth bass and sunfish, which are pretty easy but not worth much. The lake is more money but some of the fish are harder.