Types of Communication Which Promote Interaction
The true test of effective commcommunication skill> is when a dynamic interaction happens between two or more people.  A relationship evolves when communication happens.  Communication is an exchange of ideas, beliefs and emotions, and this exchange flows in a two-way process. 
Verbalize it well

People communicate with each other through oral and written means.  You can be effective in verbalizing your ideas if you convey them precisely and clearly in words and in writing.  Use words which are short, simple, and easy to understand.  Remember that the goals of all types of communication is to express, not to impress, so try to stay away from useless jargon.
Above all, what captures and keeps the attention of your audience is the content of what you’re saying and the manner in which you deliver your message.  Adjust your tone to the occasion.  Keep your tone formal yet genial if it’s a business or corporate gathering, and be warm and conversational if it’s casual talk.  Modulate your voice so that it’s not too loud or shrill for comfort.  Even if you get carried away by the passion in your emotions or the excitement in your speech, try to control your speed and make occasional pauses.  Pause, if not for emphasis, then to allow the other party a chance to speak and you to listen in return.  The same applies to the exchange of letter, emails, and other correspondence.
Learn to listen

Most of those who know a lot of things have been good listeners and observers.  There is quite a difference between being knowledgeable and educated enough to share as many words as you can from being a learned man who knows when to speak and when to shut up and listen.  Other people have their say in the world, too.  If you try hard enough to listen, you not only hear what the other person is saying in words but also what he or she is trying to convey in actions and behavior.  A closed or slammed door means what it says.  A handshake seals the deal.  An affectionate hug deserves more hugs back.  Some types of communication are hard to read, and it takes a person of good perception and awareness to be able to correctly see through the needs and emotions behind the body language.    This is how interaction happens with or without words through verbal and non-verbal means, respectively.
Receive and respond

Once you have received a message, the cycle is completed and interaction happens when you send back a response.  The reply may be favorable or not to the sender, but any response is better than no reaction at all.  It may come in brief forms like a verbal yes or no and a simple nod or pat on the back which is already understandable and meaningful to the other person. It may also come in the form of an endless exchange of stories and narrations on a variety of topics you both understand and enjoy.  This is when interactions are at their best.   

        
Communication skills are much like relationships.  They are interpersonal in nature, they need to be developed and enhanced, and they reward you with very satisfying outcomes if you make them a priority in your life.