Which books should I study for jee main ??? And other competitions

Dear Ravinder
For mathematics,  follow RDsharma
For physics, concepts of physics by HC VERMA
chemistry you can find so many books but I like the ones with Arihant trademark.
Apart from this some NCERT books are available in offline and online, just go through the different models available on every chapter end.
If you're confident enough like you can crack JEE then go through the model question papers in online and the best thing is start your preparation by knowing the weightage of each and every topic in subjects.
If you want more information regarding JEE click on the below link.
JEE

All the best.