***** NOT A TEACHER *****
Hello, Kumar:
Do you wish to have a larger vocabulary?
If you do, here are two suggestions:
1. Read widely. Do NOT look up every unknown word. After you have read an article, use a good dictionary to look up one or two unknown words that kept appearing in the article.
2. Do what students do in many foreign-language classes:
a. Write a new word on a small card.
b. On the back, write the definition and three sentences that use that word.
c. Whenever you have a few extra minutes, review those cards to see how much you have remembered.
d. Yes, it IS boring. But many necessary things are boring.
e. You could also make a game out of it with your friends. (A person gets one point each time s/he remembers the definition of a word and two points each time s/he can recite one of those three example sentences.)
Remember that even native speakers have two vocabularies: one is all the words that a person uses in conversation and writing; the other is all the words whose meaning a person knows when s/he reads or hears them, even though s/he never uses them in conversation or writing.
Good luck!
James