In addition to the good susggestions given by other members, I suggest you to follow these steps.
1) Develop a friend circle with those from states other than your native state. This compells you to talk in English.
2) while making a beginning, only talk simple English and do not try to use high sounding words for effect. You may get stuck.
3) Jot down the common situations and frequent situations you go through daily in the office particularly as well as outside of it and develop vocabulary to communicate in such situations.For example, when you have to meet your boss in the office to give a daily report about your work, you know what is to be told to he boss. Develop vocabulary for it.
4) Read short stories which are often written in simple language and lucid style and try to grasp the vocabulary and the particular context in the story. This will enable you to understand the connection between the context and the particular word.
5) Read the editorial of a standard English paper daily and write down two words daily which are not known to you as one menber suggested and write it's meaning and thareafter compose a sentence by using those words.
6) Watch BBC, Discovery channel etc and listen to the conversations in them to gain an accurate pronunciation.
7) Watch television debates on Indian news channels in English.
8) Write some thing about an incident or event in English. this improves your flow.
After this initial foundation, you can develop vocabulary of higher level.
B.Saikumar
HR & Labour law Advsior
Mumbai