Great Notes: Make great notes without wasting time on it. For example, when I studied the interior of the earth, from NCERT, my notes looked like this.
They were visually appealing that every portion was summarised succintly by an image. This boosts your recall of the topic. Many a times, even when the information doesn’t come to mind, the image definitely would.
Create offensive, compelling stories: To remember lists, I would create really offensive, compelling stories that would remind me of the list. For example, my list of endangered animals started with “White Bellied Heron”. The first image in my story was my favorite heroine showing her belly, thus recalling the phrase “White Bellied Heroine → White Bellied Heron” to my memory. I can still recite all the endangered animals from my list without having revised it over two years. This technique is called Association. I even had doodles of the stories I spun for the purpose. Try to make them as offensive as possible so that your recall will be higher. This is supported by science.
Revision: Revision is very important. Without revising what you have learnt, you are setting yourself up for failure. Keep a schedule for revision and stick to it. It is more important to revise than to cover new topics. Certain topics like polity should be read everyday.
Discussion: Discuss topics you have studied with others who are preparing. Never enter into discussion before you have read the topic. Never discuss with someone who has not studied the topic. Both of these generally end up taking a lot of time and is counterproductive. If both of you have your basics covered, then discussion covers the shortcomings in your reading. For example, inthe “Drainage System of India”, the names of antecedent rivers are scattered within the NCERT lesseon. I had not noted them. In discussing with my friend, I realised that rivers like Subansiri and Sutluj are antecedent. It’s not that I hadn’t read it. I hadn’t paid attention.
Mnemonics: Use them sparingly. Otherwise remembering mnemonics becomes a task by itself. Never have more than a few or you will think that you know the portion, but end up with some meaningless word or sentence which won’t make sense for the life of you.
Interconnect: Many of the topics are interconnected. The more connections you build, the better you remember. These connections can be meaningful or otherwise. For example article 123, 312 of Constitution can be studied together as All India service and Ordinance making power of the President. While studying Farming methods in Human Geography, you may note that slash and burn is practiced by tribals. When writing an answer in history of Tribal economy, you can go ahead and put this in for any tribal group and it will hold. Create as many connections as you can.
There is no one method which can work best. Many people discourage by hearting things. There is nothing wrong in by hearting stuff. But rote learning without applying your mind to the topic generally would result in forgetting stuff. Instead spend some time on the material and then combine both. Rote Learning + Creativity. This will ensure that you won’t forget what you read.