Hello there, first of all know that this 12th paper is not your life okay but yes it is still a very crucial phase of your career from which your base of career will be starting

To improve your maths or to ace in your maths exam by removing your backlog here are some study tips for maths which definitely works as u have used it to

The more you do sums the more you know your strength and weakness  So as a student who was so bad at math but still scored well enough I used to write down the sums again and again even if it is 7 times because once you get to know that you are great at this topic and week in other you usually take the sum which you know already but that's not how we can improve our backlog of maths

Don't fear your fear of maths the more you tend to do the sums and equations the more you will get used to it . And once you get used to it it maths becomes smooth like butter

So all the best and definitely try this