Character and Other Issues in Marital Communication

I used to think that communication would be comparatively easy within marriage, that the period before marriage might be filled with communication awkwardness, but marriage would be a golden state where all the difficulties would have been ironed out....
However, from what people say, it seems that for many people, real difficulties in communication only begin within the marriage itself. If you are experiencing difficult communication within your marrige, what can you do to improve things?