Imagine how you might act or react in their shoes.
Jesus made it clear in one of his teachings if you are without sin, be the first 2 cast to cast a stone to d adulterous woman"
Human beings In general are always quick to judge without considering how they might react in the shoes of that person..
But like u said above, communication is the best key for interpersonal relationships.
In some cases were the person is an introvert, how do you relate with such people?
Agreed.
With dealing with introverts, you have to cue in on facial expressions and body language and read them, moreso than extroverts. Perhaps you can develop a language in which to communicate, or key words and phrases.