The proper way to intercept a glide slope is to use gentle pitch inputs that anticipate the changes in flight path from the power reduction you need to make to start descending without speeding up. This is to short cut the airplane's natural tendency to hunt for its trim speed when power is reduced without making a pitch input. Once on-slope and on-speed, the critical item is use of trim to get the airplane flying hands off at that speed on slope. Then all that are required are gentle pitch/power inputs to hold the slope.
An ILS glide slope is a unique situation where you modify the normal pitch to speed technique because the priority is to stay precisely on a horizontal sloping path and making power changes and waiting for the airplane's static stability to take care of the speed is much too laggy. And this is basically what autopilots do - they pitch to slope, and you just manage speed with power, with the autopilot taking care of trim, to the extent that the servos need to do so to reduce servo loads, in the background.
For hand flying a glide slope, the key is to know roughly what the power setting should be, and roughly what the pitch attitude should be while on slope and on speed. As the needle comes down, you pitch over and make the power reduction at the same time so as the keep the airplane close to its trim speed through the transition.
Once on slope and on speed, you note the precise pitch attitude that exists, and concentrate on holding that attitude in your cross scan. If you start to drift up, you pitch down one or two degrees and no more, make a small power reduction, and wait... if not enough, make another degree or two of pitch/power adjustment and wait. When back on slope and all is settled down, trim if/as required. Proper use of trim is critical because you need to achieve a condition where the airplane naturally wants to hold the desired path/speed, and if you are out of trim and have to hold pressure yourself, you will inevitably relax without realizing it and drift off path.