IIT

To score good marks in class 12th, is not a difficult task. Proper strategy and time management can help you to get a decent score.
1. You should follow a strict time table.
2. Go through your textbooks.
3. Point out those subjects in which your performance is not up to the mark and devote extra time to it.
4. Solve at least 10 previous year board question paper.

No, you cannot appear for JEE Mains exam. In order to appear for JEE Mains exam, you need to complete your HSC education.

The fee structure for B.Tech is 5 lakh rupees. For M.Tech, the fee structure is 2 lakh rupees.

The average salary package will be between 6 LPA and 8 LPA.

Basically, some faculties from IITs provide you with some online videos which might help a lot for the preparation. There is also in news that in the beginning of January 2017 IITs will provide tuitions through dedicated DTH TV channels and internet to the students of classes 11th and 12th aspiring to join the institutes. Also, NCERT will prescribe the problems that students would have to solve. So, kindly check about it. You may be provided with some assistance.

Yes, you can get admission in IITs. You have to clear appear for an IIT JEE exam and get a good rank.

You can consider:
1. IIT – Kharagpur.
2. NIT – Jalandhar.
3. NIT - Hamirpur.

Almost 80% of the paper will come on the basis of NCERT syllabus, so make sure your basics of physics, chemistry and mathematics should be clear. You can also join a crash course after your board exams from any of the finest institutes or you can purchase some reference books.
All the best.

Hi Suraj,
FITJEE - Patna is the best option and its fee is for Rs.2 lakhs for 2 year program. If you want less fee, then you can opt Mentors Eduserv, as the fee is Rs.1 lakh.