Hey!

JEE Mains is a national level entrance exam to take admission in top NITs/IITs of India. Gujcet is a state level entrance exam to get admission in top colleges of gujrat. For all these exams, you need to first clear 10+2 boards exam with the minimum aggregates which is 75% for JEE mains (relaxed this year). Boards exams consists of basic syllabus of physics chemistry and mathematics, English also(except optional subjects). And other entrance exams mainly consists of PCM but in some higher level. So, if you want to prepare for the exams, you need to prepare hand in hand. Syllabus of exams is almost same. Entrance exams consist of multiple choice questions where as board exams questions are subjective. Once you are done with a topic, try giving some extra time to it by solving some jee  questions. It is advised to study some higher level books which will not only help you in entrance exams but also to perform better in boards. Also, try to solve somev previous years problems to get to know the exam pattern, it is not particularly for JEE mains or entrance exam but you should also try solving previous papers of board exams.

Hope it helped to clear your delimma

Thank you