how can I get good rank in jee mains?

Hello Varsha!!
To get good score in Jee mains you should be more concentrated towards your studies. Competition is very tuff for these kind of entrance examinations.Okay!!..when comes to preparation firstly, you should know the pattern of the paper and important topics and also weightage of topics .This makes you to guess the difficulty level of the paper .So, set the timetable for your preparations. Finish the weight age topics and important topics first. Ncert books are the recommended books for mains examination apart from this concentrate on other selected books which helps your concepts better. Make a notes while preparing and note down the important topics. After completion of topics just take the mock test in the official website of mains and also practice the sample papers to know where you are at preparation. I can tell you the suggested books for each section also, so
for mathematics:
Ncert part1 and 2
Class 11th and 12th by R.D sharma
Trigonometry and geometry by S.L Loney
Problems in caluclus by I.A Maron
For physics:
Ncert part1 and 2
Concepts of physics by H. c verma
Problems in general physics by I. E Irodov
Fundamentals of physics by Resnick, Halliday and walker.
For chemistry:
Never books1 and 2
Physical and organic chemistry by O. P Tandon
Numerical Chemistry by P. Bahadhur
Concise inorganic chemistry by J.D.Lee
You can get the weightage of topics in each section in the below link:

https://www.google.com/amp/s/engineering.careers360.com/articles/jee-main-syllabus-weightage/amp?espv=1

And.. Here is the link for previous years question papers with solutions just go through it

https://engineering.careers360.com/download/jee-main-sample-papers-previous-years

And here is the link for some more preparation tips to prepare better for JEE mains:

https://www.google.com/amp/s/engineering.careers360.com/articles/jee-main-preparation-tips/amp?espv=1
I hope this information would helps you. Do prepare well.Good luck achiever!!