Other people do other things, but here is my take on it, which only works if you are shooting sheet film:
The basic premise of the zone system is to expose and develop in such a way as to produce a negative that can be printed easily. Variable contrast papers give us a knob to turn in the darkroom that didn't exist when the zone system was first developed, so I use a process which is geared towards getting negatives which are easy to print in the darkroom.
Step 1 - determine exposure:
I always use the same film, which I rate a box speed, which is a little fast. I meter on the darkest part of the scene in which I want to retain value and I place that in Zone IV. I look at the scene and determine if it is about normal, super contrasty or kind of flat. I expose two sheets of film, exactly the same.
Step 2 - develop:
I usually develop the first sheet nominally. I always use the same developer, so I know what to expect, I develop one sheet of film. If the scene was particularly flat, I develop for longer (usually ~20% more time), if the scene was really contrasty, I develop for a shorter amount of time. I then inspect the negative - and sometimes make a print or two from it. If I am happy, I process the second negative the same way, and I have a spare, if I want more or less contrast, I process the second sheet of film for more or less time.
If I am feeling particularly nerdy, I will use a densitometer on the negative to figure out if I want more or less contrast, but I am usually happy just looking at the negative. on the light table, sometimes the image is really contrasty and that is what you want, sometimes not.