West Bengal

It is good that you are pretty serious about cracking these exams
First of all note that your board percentage has no role to play in deciding your JEE rank from this year on wards . So if you can make it a 75% + in your boards that is more than sufficient .
Coming to your preparation
since you are from a state board make sure that you purchase NCERT books .
Read these books simultaneously along with your board books. It is most important to highlight important points from NCERT
Maintain a formula book for each subject note down all the formulae you come across and derivations if necessary keep revising the highlighted points and formulae
Practice from HC Verma for physics Arihant series for mathematics P bahadur numerical chemistry or GRB for physical chemistry JD Lee for inorganic (Balaji publications is also good)any reference for organic is fine
all these things only after NCERT
Apart from these you can practice from Arihant DPPs
and you must solve previous years questions after completion of each chapter
All the best !

Dear Manash, before joining Globsyn Business School I myself have spoken to a lot of alumni across different batches and like you I also inquired about placement. Everyone has said that you don't have to think about placement if you prepare yourself well with the opportunities provided by Globsyn Business School and the same thing I have seen when my immediate seniors went for their placement process. Most of my seniors have got good placement and are currently working in different international and national organizations. Our batch has got great Summer Internship Project. The only reason you may come across few adverse comments is due to couple of students who despite getting multiple interview opportunities could not convert one. I have seen a couple of my seniors appearing for 8/9 interviews but could not convert a single one and our placement team is still supporting them with training and other inputs. So be less assured that you that Globsyn placement team will take care of your placement.