The cut off varies college to college. To get admission in top NITs you need to score more than 230 & for Lower NITs you need to score more than 120 as a General category. And for others each college has different criteria (Jee Main Score & Eligibility) to take the admission. so if you specify then accordingly I can help you about. You can check this year JEE main cutoff with given below link.

JEE Main Cutoff

Good Luck!

Try to score more than 150 marks in JEE Main to get good NITs in other state quota and more than 230 marks to get CSE branch in top NITs.

Below are some preparaton tips to crack your exam

1- You should plan your own time-table. So, your syllabus is covered on time and you get proper time for revision. You should focus on important topics you can also make your important notes which will help you at the time of your revision.

2- Try to clear your concepts. so, you can build your fundamentals strong. You acn take help of NCERT books for that.

3- Refer previous year paper to understand the exam pattern and level of exam. 

4- You can solve complete mock test series for your practice and to know your strength and weakness. So, you can work upon them.

All the Best!!