Hello Lily , To improve your oral English you have to improve your reading ,listening and writing skills all together,because they are all interconnected . When you read more ( of course provided you look up new words you read so you probably would start with simple texts matching your level at the moment be it a beginner or intermediate level) you will increase your vocabulary which will provide you with certain amount of words you can use in your oral speech . The listening will help you pronounce correctly . You can use any audio material such as songs or online audio lessons etc , you can watch movies to listen to more words ,that makes learning an entertaining process as well . To apply all that and practice you have to speak ,you can repeat after audio lessons loudly ,you can chat with natives to apply and use the words you have learned previously, because in the course of repetition the vocabulary will be memorized . Doing lots of exercises ,grammar and sentence building ones will help you form correct sentences while speaking .The more you exercise the better sentences you would be able to speak with lesser grammar mistakes. It is a gradual process ,where improvement is achieved through continuous learning Best Wishes :)

For a Chinese student,it will be a hard time to practice their spoken English .such as me ,i used half a year to practice my spoken English .At the beginning ,i can only understand 70% of the foeigners,and i was too shy to speak ,and nearly a month passed by ,i express myself the simple conversations,and then ,there months passed by,i can express myself freely !~so ,i just want to say ,persist practicing and speaking ,and you will win at last !~

Amen to that written above me. In addition to that, you better find someone whom you can converse with in english and can correct you in your mistakes. The more you use the language, the more you will be comfortable with it. Italki language partners can be a good place to start.