I need to improve in English language.

I'm looking for a new job. After I applied to the company I want and submitted my resume, I will prepare for the interview with the interviewer. It is in the automotive department of the company which is managed my foreigners. I worry about my speaking and communication skills. So I really need to improve my English writing skill first. Please help me to use the correct words in a sentence. I think that if I could write correcty in English, I will be able to speak well, too.