A common general communication is culture, this is because a hand gesture can mean many different things in many different countries. This applies for the thumbs up, in most countries the thumbs up means its good, but in Bangladesh it is an insult and in certain parts of the Middle East the thumbs up is considered a very insulting thumbs down. Another hugely offensive gestures is the "V" sign! In America it means victory but in many other countries such as England and Australia it is extremely rude. A way around this would be to research the countries cultural ways so you don't upset anybody.
Audience is another key barrier, if you are boring your audience or they aren't understanding you then, they will stop listening and do other things to occupy themselves. The best way to get over that is to make sure what ever you are doing suits the audience. If its a group of children then create a presentation that would keep them interested.
Another common Interpersonal communication skill is Language. If you don't speak the same language as someone else it can be some what difficult to communicate with them. You need to be able to get around this because you wont always be talking to someone who is form the same place or country as you. Not only is it languages it can be accents, if someone has strong Scottish accent for example you would struggle to understand them. A way around this could be to take someone with you who can translate languages for you.
Not only that remember that when you are writing that you need relevance in your work. If your work has nothing to do with the topic then will not take you seriously, the best way to make your work relevant is to make sure that you know what topic it is that you are focusing on. Once you know the topic all you have to do is incorporate information about it.