A 3 degree glide path equates to 320 feet per mile. So you can use your ground speed to tell you the required rate of descent - 120 knot ground speed requires 640 feet per minute ROD

Any aircraft will fly at a given body angle and power setting at a certain speed for a given weight. Pilots get to know the relevant power and pitch settings for approach. An A320 fully configured on approach flies at 2.5 degrees nose up at c1.05 EPR. Nose low on the slope and you are too fast, nose high on the approach and you are too slow.

All pilots are taught in basic training how an aircraft feels to fly in the regime close to the stall, which is to say with high AoA. It is a flight regime where you feel uncomfortable- the hairs on the back of your neck start to raise - unless it is deliberate, as in aerobatics etc.

so there are many clues as to whether you are coming down too quickly, not to mention the glide slope indicator!