In addition to the good suggestions given by other members, I suggest you follow these steps:
1. Develop a friend circle with those from states other than your native state. This compels you to talk in English.
2. When making a beginning, only talk in 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 the boss. Develop vocabulary for it.
4. Read short stories that are often written in simple language and a 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 member suggested. Write its meaning and thereafter compose a sentence using those words.
6. Watch BBC, Discovery Channel, etc., and listen to the conversations in them to gain accurate pronunciation.
7. Watch television debates on Indian news channels in English.
8. Write something about an incident or event in English. This improves your flow.
After this initial foundation, you can develop a higher level of vocabulary.
Regards,
B. Saikumar
HR & Labour Law Advisor
Mumbai