RCPS Many people from different countries have improper intonation because their teacher had improper intonation. In many situations, being monotone is better than having bad intonation. The worst is when someone goes up and down too much on every word. Another thing you should avoid is to end high at the end of a sentence.
To correct improper intonation, you need to remember to start high and end low. You cannot do it any other way. I recommend going to the interview section and listening to one of the audio files provided by a native speaker. You will hear proper intonation. After listening to the audio, record yourself and listen to it. Does it sound the same? If not, then find the areas that are dissimilar and make the necessary corrections.
A common mistake of people who obtain English fluency with improper pronunciation and intonation is the speed in which they speak. Because they do not have perfect pronunciation and intonation, it is difficult to understand people who speak too fast. This is the biggest problem I have seen from people who gain confidence in speaking.
In order to improve your communication, and to hear "excuse me" less often, it is important to have the correct speed of speaking. For people with confidence, my advice is to slow down and to speak clearly. Don't blend words together too much and make sure to separate words with a small pause for words that are difficult to pronounce.