Intonation

Like the intonation of many other languages, the English one is all but constant – it goes up and down to an extent that often surprises people without considerable experience.

It is impossible to give guidelines here, but if you feel you have a problem with the intonation and are often influenced by the intonation of your native language, listen to English radio (news), Ted Talks, etc. and try to grasp the sentence tone.   

At https://www.youtube.com/user/doingenglishDOTcom?feature=watch there is much help and advice.