I think the best way to improve intonation is to mimic a native speaker. Try to find a native speaker whose voice you enjoy hearing. Since you want to follow that person for a very, very long time and on a daily basis, you have to make sure that you can hear that voice over and over and not feel annoyed. I like to follow Hillary Clinton and Katie Couric because I like to hear their speeches. Their recordings and transcripts are relatively easy to find.
I have tried to follow VOA but could not do it. Either I have not found my favorite voice there or something else. I also found VOA normally is too slow, which may be good when you want to improve your listening skills or your pronunciations. But for intonation, VOA does not help me much. I’d rather like to find someone who speaks at a normal pace.
When practicing, I try not to read a paragraph myself. Instead, I try to follow the speaker several times until I feel I can follow her pace and intonation easily. I then try to read the paragraph by myself and record my reading. It is almost like you practicing with a cane until you are confident enough to walk without it. By listening to your recording and the original speaker’s recording, you can hear the difference between your reading and the original voice. Adjust yours when you hear a difference. Keep repeating this and improve accordingly. It may take days or even weeks to conquer one paragraph. But as you practice more, you’ll find that it takes less time. The goal is that someday, you won’t need to practice and can read just like the speaker!
This is just my personal experience. It may not be the best practice. Try it if you are interested and please let me know how it works for you.
