What should I do to speak well in English?

Firstly you should read English newspapers and novels as much as possible and refer dictionary whenever you don't understand any word. Make a habit of communicating in English and while doing so dont get nervous if you make any mistake. But you should learn from that mistake and never repeat the same. You should also watch some good English series to understand accent. 

You want to practice English daily listening English program like song news movie and reading books novels news paper this will help you in self correcting the vocabulary words and improve your self-confidence speak to othersinagain and again learning listening writing and reading this will help you to speak English fluently daily you want to spend time for English you gather your friend together and talk with them in English 

You first need to clarfiy your concepts in English. A large proportion of the Indian population makes mistake in subject-verb agreement, pornunciation, and wrong usage of the word due to lack of understanding of the meaning of a lot of words hence, I believe these concepts should be clear then one can move on to practising speaking English with Either native ENglish speakers or wiht people who are fluent in English (i.e. they have all the above concepts in place).

Speak (converse ) in English more often .Gain feedback from the person talking to you.

Also stand in front of the mirror and speak something and assess your mistakes and keep practicing often.  Watch television news chanel in English..

Read books that interest you. Watch videos of famous people anchoring or presenting something to the audience. (Shahrukh Khan inspiring videos)