Let’s keep it short.
No need to read bulky books by Amartya Sen, Gurcharan Das and likes. Be smart and utilise time optimally. If you want, you can read their summaries from internet.
Read PM/President/Vice President speeches. They have all the ingredients you need for a good essay viz. facts, vision and catchy language.
Remember few quotes and use them from now on. Practice makes a man perfect. Don’t procrastinate. Write an essay and get it reviewed. We have seen people getting marks in 60s-70s who are careless.
At least remember quotes/phrases related to India as you can use them in many topics like education, governance, corruption, poverty, values etc. etc.
That’s it. So, the perfect recipe for an above average score (130+) in essay is :
(1). Read PM/President Speeches
(2). Remember few quotes/phrases etc.
(3). Write few essays and get them reviewed