Those who are learning English while making a complex sentence or talking in English, get stuck in many places. In that case to improve reading, writing and speaking in English vocabulary is very important.
Here are few tips:
Read: There is no alternative to reading. The more the reader, the more he will learn.
Content: In the beginning start reading small text books, newspapers, articles etc. If you have patience then read nobles, fictions etc. Take a good look at the new words you see there. Read the entire sentence again if you don't understand. Use dictionary if you find new words and check their meaning also.
Practice: Surely practice makes a man perfect. Use the words you have learnt. English Vocabulary will grow.
Build the road: After learning an English word, see the example of those words. Now create some examples yourself. This will boost your confidence.
Play with the words: Everybody listen to music especially English songs. Why not get some benefit from it! When you listen an English song, read the lyrics while listening to it. It will help you to improve the pronunciation as well.
Shyness: 'I can't talk to anyone in English or I might say something wrong, people will laugh'... one should never think of this! Nobody is perfect. As human beings we learn from our mistakes :)