"Sticking" to one version is of course the best way. As a student in the Malaysian education system, it was British English but coming to study in the States, I had to do a little bit of relearning. Suddenly, I had to spell "standardization" instead of "standardisation"! And now, after more than 10 years, I have to relearn as am working on my master's degree in one of the local universities -which uses basically the British English. Somehow, with the teaching experience, it is not that difficult to adjust. May be because I was constantly telling my students that this is the American version every time they corrected me! Anyway, for both British and American accent, the sort of standard version one hears on Tv or movies would be acceptable, I guess. Because once you start using that Cockney accent or the Texan twang, I am lost! Well Dave, a friend did her bachelor degree in Australia, then she went to the States to her her master's...the Americans could tell that she was "from" Australia straight away...well, we claim that we speak "without" accent, but somehow, to be "accepted", we still "mimick" to a certain extend.