How do I know when my wine is properly reduced? I guess it can be subjective according to tastes, but some reduction is required. If I could know what I am trying to do away with in the reduction process (alcohol, raw bite or volume) then I could adjust according to my subjective taste and dish.

Some general guidelines about how do you know when your wine is reduced or what to look for in a reduced wine would be useful.
The goal is to evaporate alcohol and concentrate flavor.  If adding wine to a mirepoix, or sofrito...some sort of early stage aromatic vegetable... reduce the wine almost until the pan goes dry, but not dry enough to cause sticking or burning.  The flavor will be absorbed into the vegetable and you are good to go.  If there is another instance of wine addition that you are considering, please specify.