I have used the light meter method to great effect. Simply watch the meter in the viewfinder as the polarizing filter is rotated. As shutter speed slows, polarization is occuring. It is important to note that not all scenes have significant polarized light. Polarization is maximum when you are aiming at 90 degrees to the sun and minimum when aiming parallel to the sun. Thus, if the sun is in the west and you are aiming to the west or east, do not expect to get much effect from a polarizing filter. The same is true on cloudy days and when the sun is directly overhead.
Not being able to observe directly the darkening through the viewfinder, as with an SLR, does make the process a bit of guesswork. Sometimes, maximum polarization renders sky or water unnaturally dark, but you cannot know that when using an indirect method. Therefore, it may be useful to "bracket" the polarization, much as you would with an exposure compensation dial.