You should practise knowledges that you have learned by speaking English regularly. For example, when you go shopping, you try to name things that you want to buy in English, note words you haven’t known to look up dictionary and learn more.

When you talk with your foreign leader or coleagues, whether your vocabulary is limited or grammar is not sure, you should try to use simple words to express your ideas.

Besides, you can ask your friends who are good at English to correct your mistakes, give advices to help you overcome your limitation gradually. Being wrong in English is accepted by yourself because English is not your mother language. You have right to be confident because you have ability to communicate in two different languages.