hey..just be yourself..dont get embarassed with your english..dont ever think that those natives speak english well..no they don't..they have lapses in their grammars too..its not a good idea to learn their pronunciation since they will make you stupid, unless you go to US or UK to immerse yourself totally with their culture and lifestyle, by then, you will be able to adapt their pronunciation..there's no such thing as perfect english..those natives are just mumbling with no sense at all..and they still look stupid pretending that they know everything...watching english movies, reading books will help..