Here we go again.........
As Mono has said, the stick and the throttle are interrelated. There is no one technique for approaches, rather a combination.
For example, if you find yourself high on an approach and then reduce the power whilst keeping the nose in exactly the same attitude, then you'll start to slow down as well as sink faster.
So if you are high, reduce power and lower the nose slightly, if low increase power and raise the nose.
All controls in an a/c effect something else, the trick is to anticipate what will happen when you make any movement of a control.
It doesn't matter what you fly, from a PA18 to a 747, the basic principles are the same, the difference being the inertia of the a/c. Believe it or not, speed control in something big and heavy is actually far easier than in a light a/c, but if you do stuff it up, it's harder to get something big settled down again, hence the check at 500' AGL on approach to make sure you are stable. (Speed, flightpath and configuration.) If you aren't, you go-around.
Getting an approach stablised early is critical, for a start make sure the a/c is trimmed out correctly. (when will most instructors start teaching this correctly!) Once you are trimmed out at the right speed, you'll find it only takes small control movements to keep the a/c where you want it and everything will suddenly seem so much easier.