What are the most preferable time by many tourist to visit Times Square as a first time visitor?
To see the actual Times Square without crowds or other distractions, early-ish in the morning. Say <9am.
To see daytime Times Square, meaning tourists (it's just a tourist trap these days), creepy (sorry, they are :) characters, shopping, and trying for discount shows, say lunch time to mid afternoon, 1pm - 3pm.
To see nighttime Times Square, meaning lights, video marquees, the scrolling new ticker and other 'entertainment', anytime after sundown or after your show.
Note, people who live and or work in NYC usually avoid Times Square if at all possible.
Source: Personal observation from a window in my building.