Talking on the phone in English is much the same as talking face-to-face - it depends on the context! If you are talking in English to a friend you talk in the same way you would face-to-face and if you are talking with clients in the phone then you use formal English in the same way you would face-to-face. For example "Hi" is not good, "Hello" is better but "Good Morning/Afternoon/Evening" is best. "Do you want" is not so bad but better is "Would you be interested in". "Wait please" is ok but best is "Please hold the line for a moment". I hope this helps.