Firstly; understand the concept thoroughly.U need to have basic knowledge on mathematics as well ...for ex:-Finding out roots of a Quadratic equation;Vectors;Differenciation;Integration;Binomial expansion;Logarithms;Exponents;Arithmetic progression;Geometric progression etc...Secondly; practice various types of model questions related to the topic from ur reference materials & books.Thirdly; go through a analysis of previous years question paper patterns and solve them...Lastly; keep memorising the formulas time to time & remember to know their derivation as well ;coz it turns out to be helpful in the time when u r confused with the formula...During exam don't be in a hurry during solving as each silly mistake counts & turns out be a -ve attempt. So while ur solving don't panic about the time just note done ur solving in a neat manner so that u may not confuse & not do a silly mistake...Be calm & don't be in a agenda to solve each & every question mentioned in the question papers..Mark only those answers of which u r sure about..And all the best !...

Friend, don't get nervous...Study thoroughly and smartly...Study only those chapters which are important for exams.And Revise it daily and practice numericals alots..And for clear your concepts, Go to YouTube Channel of Physics Wala, Vedantu...As your choice...Mind It...DAR KE AGE JEET HAIN...JEET KE AGHE NEET HAIN..Thank you..