Communication is an awesome tool, but it can do much damage if not used properly. This holds true in all types of situations.
As (hopefully) everyone knows, communication is a two-way street for the parties involved. If you are attempting to communicate with another person, you convey information, and they convey information. The key is for each of you to accept the conveyed information. I'm not talking about just "hearing" or "seeing", but interpreting and understanding. If one of you interprets the information incorrectly it could be something as small as a simple misunderstanding or as large as an personal insult (that does lasting emotional damage).
Simple misunderstandings can easily be fixed and may not even be apparent to either party. However, larger miscommunications that cause deep pain can be much more difficult to overcome. This can lead to the severing of communication between the two parties or interpretation based primarily on suspicion.
The best way to prevent this kind of problems in communication is to ask questions about what the other party is attempting to communicate to you when the communication may be ambiguous.
Another way to prevent this (that doesn't guarantee anything, it just helps) is to have a personal relationship with the person. One of the key "hot-button" issues in a person's life may be the past, current experiences, and worldview. Getting to know and understand these things will help you to communicate with them in a way that is more likely to be interpreted properly. But of course, this is not easy or brief. It does require that you first be the one to interpret and understand properly.
Another part of successful communication is understanding the perspectives from where someone is coming. Understanding the experiences can shed much light on their current behaviors. Not only must you get to know the person, but you must get to know the psychological issues.
Of course, this is not to say that doing research to this level is required to be effective in communication, it just tends to help tremendously. What's really nice is that this kind of information can be gleaned from sources that may not be specifically targeted toward a specific psychological or sociological topic. I have been reading several books about marriage, raising children, and communication between spouses. They have given me much insight into communication in general and how to appeal to some of the deepest of emotional concerns of other people.
It will also pay off to think ahead. One of the main things to always keep in mind while you are conversing with someone is, "Will what I'm about to say tend to alienate the person from that I am trying to communicate or attract them to what I am trying to communicate." This is why many times in presenting a defense of anything that small, logical steps must be taken.
This of course, is quite important when presenting a defense for the Gospel of Jesus Christ. We could have developed the best, air-tight argument for someone who is opposed, but if we don't show the same care and love that Jesus commanded us to (and did himself), then we may be removing an intellectual stumbling block and replacing it with an emotional one. And in many cases, the emotional ones are tougher to get past.
Here's a list of scriptures in the Bible that discuss communication. I have provided this list for two reasons. First, for the Christian to have reinforcement of what I am saying; and second, the non-Christian to see evidence that the Bible accurately describes (at least, this part of) reality:
James 1:19- "My dear brothers, take note of this: Everyone should be quick to listen, slow to speak and slow to become angry".
Ephesians 4:2- "Be completely humble and gentle; be patient, bearing with one another in love."
Proverbs 15:28- "The heart of the righteous ponders how to answer, but the mouth of the wicked pours out evil things."
Proverbs 16:21- "The wise in heart are called discerning, and pleasant words promote instruction".
Proverbs 16:23- "The heart of the wise instructs his mouth and adds persuasiveness to his lips."
Proverbs 18:13- "He who gives an answer before he hears, it is folly and shame to him."
Here is the book that I am reading right now that got me thinking about all this. As I get more, I'll add them:
Cracking the Communication Code by Dr. Emerson Eggerichs
Here's Focus On The Family's Communication 101 webpage.
I also recommend Stand To Reason's entire site for finding good information for apologetics-focused communication.