UPSC Prelims has 2 papers. Paper 1 covers Current Events, History of India and Indian National Movement, Indian and World Geography, Indian Polity and Governance, Economic and   Social Development, General Issues on Environmental ecology, General Science.

Paper 2 covers Comprehension, Interpersonal skills including communication skills, logical reasoning and analytical ability, decision making and problem solving, General Mental Ability and basic numeracy numbers.

For this only NCERT books might not be helpful. You have to practise as much as you can in all these Topics. If you are making notes of 12th notes from NCERT books, because you are a Commerce student, it might help you for Mains preparation when you take an Optional subject. That is a good preparation strategy. Many Candidates focus on Mains and the Optional subject from quite early stages. But what you also need to remember is that you can only move to Mains if you qualify in Prelims. So you should also study these all these subjects at 12th level for now. Continue making notes the way you have been doing. But for CSAT, practising is the only way. Making notes might not help much in this section.

Hello Aspirant,

Making notes of every subject is a good strategy and it definitely comes in handy in every examination. These notes are perfect for revision. For cracking such examinations, a candidate needs to study a chapter more than twice. And these short notes are the best for them. And at the end when the examination dates are closing, through these notes you'll have revision materials.

All the best~