I would strongly advise you to do the Masters in Science Communication in DCU. It really gives you a feel for the different kinds of media and ways of explaining things. And it's a good place to make contacts, which is also useful.

I would also recommend that you read science books. Not textbooks, good popular science books are just as useful for this kind of work, as it's already been broken down into simpler language for you. And only read the ones that you're interested in - it shouldn't be a chore to read them.

But I would recommend reading outside your subject area, so if you're into physics, then read some books on biology and vice versa (everyone should read Stephen J. Gould).  However, the more knowledge you have, the more questions you'll be able to answer.