How do I attempt questions in literature and answer long answers on John Donne, John Milton, Francis Bacon and Shakespeare? What all should I include in any answer pertaining to them?

I believe an examiner looks for evidence of first hand reading of the author or the text in question when you attempt long answers on such writers as you have mentioned. The next thing is to have your own point of view about the author or the text’s significance. A good background reading of the work and the literary criticism pertaining to that is required if your answer is for a PG or a higher level exam like UGC NET or UPSC ICS.

Questions can differ, based on summative assessment of the text like Summarize Milton’s Heroic Argument in the Paradise Lost or critical assessment of how Milton’s fallen angel turns out nearly equal to God courtesy Milton’s heroic diction and grandiloquence. Appropriate quotes inserted at the right places will certainly elevate your answer.