In Vietnam, there is common fact that students are taught English early from elementary schools until universities; however, they are not able to speak English well. They learn a lot about grammar, vocabularies but they are lack of practice.
As children learn English, my approach to learn English - I mean here speaking and listening skill - is to listen and repeat. The key idea is that let take any English conversation samples and listen and repeat them.
The following website is one I strongly suggest you to take samples and practice by them: http://www.eslfast.com/robot/
Here there are hundreds of common English conversations by which you can reference. Let try to listen about several times; in the case you are not able to understand conversations, no matter that you look at and read them. Later on, try to repeats sentences by sentences until you can speak them aloud fluently. Practice it day by day, each day about 30 minutes, I am positive that your speaking skill will advance significantly.