If you are already in IISc, then the essay on whether you should attend graduate school is probably not useful to you. After entering graduate school, the first major priority is that of choosing an appropriate research advisor.
While in grad school, the most important aspect is to write research papers. Professor Whitesides, who has the highest h-index among all living scientists, says "If your research does not generate papers, it might just as well not been done. Interesting and unpublished is equivalent to non-existent" Professor CNR Rao, who has the highest h-index among all scientists in India, gave me sagely advice, "Do not be afraid to publish"
Whitesides has written a wonderful article in Advanced Materials on how to publish a research paper. Whitesides says that one should start writing a paper at the same time one starts a research project. In fact, this was the same advice my postdoc advisor gave me and he used to say that by the time the experimental work and analysis was over, the paper should also be nearly ready.
Recently, Prof. Kamat from University of Notre Dame, who is an editor of Journal of Physical Chemistry, recently visited IISc and gave an excellent talk on writing research papers and the use of figures in the papers and ethics in research. There is also an excellent guide on how to publish in top journals. In addition to writing papers, giving good talks to a wide variety of audience is essential in graduate school.
For people like me whose first language is not English, books on writing are very useful. My postdoc advisor gave me an excellent book - The Elements of Style - by Strunk and White and it is perhaps the best known book on writing well. It is available online for free now. The best book on improving English that I have read is "On Writing Well". It is a great book that deals with grammar and other semantics in an entertaining and humorous way. However, if your English is really poor, then the above books may be too heavy and, unlike other people who recommend Wren and Martin's classic book, I recommend the book - Practical English usage - by Swan. The 2006 edition costs Rs. 260 and is available locally in IISc.
After you finish graduate school, you should be successful as a post doc. At this point, you will start receiving requests for reviewing manuscripts. I follow these tips seriously and also try to limit myself to review only three times the number of papers I publish.
Finally, you may land up with a faculty position. Becoming a successful faculty member at a research university is not easy. The book—The Effective, Efficient Professor, by a famous chemical engineering professor Phillip Wankat—is a treasure trove of information on the strategies and techniques that would make a faculty member life successful and is a must-read for all new faculty.