How can i remember the formulas properly. I fear that i may forget them during exams.

So in order to remember that  first understand the concept very well st first and don''t care about formula.

After doing that, see the formula related to the concept and solve a very simple example which uses that formula.

Then you should start practicing questions related to that. My approach used to be solving the sums whenever i finished a concept.

You shouldnot focus on chapters but on concepts in each chapters.

Later when you finish the chapter, all that you will be left with is how you can use 3 concepts all at once on a single sum.

 By following these steps you will be able to remember most of the formulas.