That's not only a good question, but also an important one
Note that I am answering from the point of view of responsible students.
So, here we go.
- First of all, make a list of the chapters you've completed (fully or partially) in class 11th. This way, you can see your progress. This will not only give you confidence, but also motivate you to complete class 12th syllabus with even more energy.
- Having made the list, you should first tick the chapters in which you are pretty confident.
This is why I mentioned at the top that this answer is written from the point of view of responsible students. A responsible student who has properly utilized his/her 1 year of class 11th will get about 80% ticks done.
- What now? Well, your focus should be on the unticked ones, because these are the ones that will hit you back in almost all the examinations you face.
- Now focusing only on these chapters, make a list of specific topics at which you are weak. A simple example of a topic can be: derangements in permutations and combinations or maybe geometric problems in complex numbers, etc.
- Now comes the important part. Get 2 books - a basic one and a tough one. Solve the basic problems of that particular topic at which you are weak. If after solving 10 questions, you feel that comfortable, move to the tough one immediately without wasting time on the easy one. Solve this tough book religiously. Sit with it, give time to every question. You will surely need more time because this topic is your weakness. But remember that this spent time will help you to overcome your weakness.
- Having followed the above procedure, I am sure you are no more weak in that topic. However, you still might not feel confident. Don't worry. I wasn't confident with permutations and combinations even after solving RD Sharma, KC Sinha, ML Khanna, TMH, FIITJEE Package, Arihant Algebra and Resonance Package. But I ended up solving PnC questions in JEE.
Well, that was about overcoming weaknesses.
Having done that, an important part remains to be done - revising the entire syllabus.
Let me tell you a secret
For good students, there is nothing called as revision
They keep everything in mind all the time.
Tell them that they have exam in 5 minutes, they will be ready.
This was told to me by my Physics teacher in class 11th, who mentored (Vipul Singh, AIR 5 in JEE 2010).
Fix that in mind and remember it properly.
So, how to develop this habit?
- Firstly start reading your own notes. They are usually concise and highlight the important points which are required in competitive examinations.
- You can read entire Physics notes in a day. Same goes for Chemistry and Mathematics. If you are fast enough, you can complete in 2 days or maybe in a single day if you are too fast.
- However, you should not take more than 3 days. If you are taking more than 3 days, then you are probably weak at a particular topic and you need to read this answer from the starting once again :D
- Having done this, the only thing remains is to start solving problems. Since you already practiced a number of problems from the weak chapters, you can now focus largely on the chapters at which you are good. Since you are good at these chapters, you can solve say 10-15 tough problems rather than 50 easy ones in the same time. Just do it!
- You should be wise enough to decide how much problems you need.
Now let us talk specifically about Physics
- You can revise all the Objective I and II questions of HC Verma to ensure you are strong at theory
- You can solve subjective problems of DC Pandey (10-15 for each chapter) to ensure you have good problem solving skills
- You can solve IE Irodov if you are aiming for a better rank
- Definitely solve the past year JEE papers (1978 onward)
The above 3 will be enough to help you revise.
If you feel that you have already done the above properly and you need something new, purchase a revision package.
Coming to Chemistry:
- You can try RC Mukherjee for Physical Chemistry
- You can try LG Wade for Organic Chemistry
- You cantry MS Chauhan for (very) challenging problems of Organic Chemistry
- For inorganic Chemistry, the best source is to solve past year papers
- TMH is the best book to revise
- You can solve the solved examples and check solutions as well
Note that if you sincerely follow the above, you can easily revise everything within a month.
Also note that you must study all the subjects daily.
A subject a day is a terrible idea.
To summarize, the best way to revise is to solve a handful of quality problems that involve a mix of concepts to check your ability of assembling concepts and applying them to solve a problem.