Here, from the BBC, is an interesting article on Americanisms. But it ends with a completely incorrect conclusion.
Britain is a very distinct country from the US. Not better, not worse, different. And long live that difference. That means maintaining the integrity of our own gloriously nuanced, subtle and supple version—the original version—of the English language.
Almost everyone makes this assumption: that the British dialect of English is “the original version.” And almost everyone is wrong. Americans did not simply invent a new language on July 4, 1776. They continued to speak the English they had been speaking on July 3—the same English they had brought with them across the Atlantic. Their tradition is as old as England’s. In fact, American English is in general far more conservative than British English, especially in grammar and punctuation. (We do like to invent new words for things, but we put them into what look like eighteenth-century sentence structures to a modern English reader.)
This is merely an observation: it doesn’t affect much of what you actually write. Use good American English if you’re writing for an American audience, and good British English if you’re writing for a British audience. Be aware of the differences if you’re writing for an international audience.
But, if you’re an American, don’t think that British usage is somehow more original or correct than established American usage. It isn’t. They’re two dialects that have evolved in parallel from the same immemorial tradition. Use your own standard American English, and be confident that you’re quite correct to do so.