There are quite a few different accents in English, and a problem is being able to tell them apart, and knowing which one you should sound like. The previous examples have all been in the American accent to make things simpler. When you are first learning English you should only try to learn one accent, and you should decide whether that is an American accent or a British one. However you should try to understand both.
To help you with understanding both accents, here is a list of some common and more difficult words in English, said with both a British and American accent. Listen to both pronunciations and see which one you most sound like.