Dear Sandeep,
Learning new vocabulary is not a big deal. You just have to be in the world you are in now. I mean, just follow the world. Observe others how they speak, mark the words or lines they use in their daily lives, just copy their words and quotes as we copy the sense of dressing of others or some good things we see in the trend. So just do that. You will easily learn new words and also how to frame them into sentences. Stop thinking in Hindi or in your regional language; this is our problem that we think in Hindi and then translate the same into English. Dear English is just a language so we can easily learn it.
My brother is in standard 10th and he is also facing the same problem as you are facing. So, I just made him cram the words or lines. Whenever I am back at home, I just give him a few words or sentences in English to remember that he will never ever in his life use in Hindi or in Punjabi. That's how he is improving his vocabulary. For example, earlier he used to say whenever he had a quarrel with someone, "tum khud ko samajhta kya ho?" but nowadays he says, "what do you think of yourself." It is just an example. I started this exercise with him a few months ago, but now he has improved a lot. If you don't have anybody to talk with, then switch over to English movies because my brother is also watching them. Earlier he did not understand even a single word, but he used to sit there for long. Now he can easily grab the words and sentences.
If you think that English speakers are very good at speaking English then you are mistaken because they don't follow the grammar but we do. One of my students is Nigerian and I teach him English as well. Though it is his mother tongue, he failed in the exam just because of grammatical errors. He used to say, "mam dis is d toughest subject." Now, can you imagine that a foreigner is saying that he cannot pass in the language that is very much his own language? So, don't lose hope. It's just you who can help you in improving your communication skills.
Hope all this will help you out.