But since this ideal situation is not possible a lot of times, we rely on coaching material.
Whether it be dams, Bhatia, marrow, prepladder, etc, all are nearly the same. Dams is one step ahead in quality of notes. Second is marrow.
Some good guide books like pritesh Singh, Devesh Mishra hold the same material as well.
So even if you get the best material, it won’t lead you to success. Revision will.
So have faith in the material you have trusted with, and repeat and revise the same.