How do you determine the proper rate of descent for landing?
Assuming you want a 3 degree glide slope, just take 5 times your ground speed in knots as a starting point. 

As an example, approaching at 90kt ground speed in a light aircraft, go for 450feet per minute. at 140kt in a jet, try 700fpm. If you're flying a jet outside of 4 miles, and the controller wants you to keep the speed up at 200kt then descend 1000fpm.

It's not perfect, but it works pretty well for a first guess, and you can adjust as necessary.

Of course, your ground speed is not the same as your air speed, and even for a constant IAS it will likely vary as you descend and the wind changes. Another way to think about this is that a 3 degree glideslope is almost exactly 300ft per nautical mile. If you're 2 miles out and 700 feet up, then you need to descend a bit faster, conversely, if you're at 500 feet, you need to descend slower.

A third related rule of thumb is that your final approach speed (in CAS, although IAS is good enough in most aircraft) is 1.3 times your stall speed in the landing configuration (Vso). So if you stall at 100 knots, you want to approach at 130KIAS.

IFR approaches are all about having an initial guess at these numbers in your head, trying them out, and then adjusting as the conditions require. If you're good at the guesses then the adjustments will be very small.