Your routine of study must be of 12 hr so that u can study approx 8–10 hrs, divide this time according to your own comfortability in each subject. Revise all the topics that u have read in std XI and XII th properly . Make short notes of all the topics revise it ,solve numericals in each topic(question bank of jee mains , wbjee& bcece) ,as much u solve numericals your confidence level goes up.Focus on chemistry mainly (physical, inorganic & organic all) because it saves your time in exam, time management is one of the important factor in exams,and in BCECE they give very less time per question as compared to JEE MAINS and also the invigilator disturb you for attendence , biometric scan and other stuffs so u have to manage time .And one thing I want to clearify u that if u want to crack BCECE with good rank u have to prepare like u are preparing for Jee mains .
All the best!!!