Dear Srinu,
First start reading news papers(editorial), english magzines and good novels. Try to understand the construction of sentences, punctuations and importance of paragraphs. Everyday try to learn the meaning of atleast 10 new words and try to construct the sentences. Every word has its own meaning for different circumstances. You have to use your wisdom in constructing the sentences. If you know the meaning of 10000 words and its usage, you can be a good writer. Reader Digest has brought out a book " Right words for right usage" Refer such books. Always go for simple sentences. Communication should have the principle of 5W & 1 H - What you want to say, whom to address, where to, when and why. H is how to draft.
It is not one day's task, it needs continues efforts .
G.K.Manjunath
Sr. Manager- HR