Hello Tommy,

I assume that by wasted you mean you scored a very low percentage. The answer is the probabilities are very very low, but theoretically, it is possible. One will have to work day and night for it. There shouldn't be anything else on your mind. You'll have to devote around 10-12 hours of your day. But to even appear in advanced, you'll have to clear JEE Mains first.

some of the preparatory tips I would like to suggest will be:

First, for clearing Mains, try to focus on your problem solving skills and time management. Whatever you learn, try to keep it in your mind as you may not have enough time to come back and revise every portion. Mains requires an average depth knowledge and fast problem solving skills along with a good time management.

for Advanced, I would suggest you to select particular topics and attaining an in-depth knowledge and practice harder level problems. you can skip about 20% of the portion but only when you have a great command on 50% and an above average command on 30% of the syllabus. But be careful while doing so. Carefully examine the question trends for previous year papers.

Some good reference books can be:

for chemistry- Mains: reading ncert line by line would be enough. problem solving for physical is necessary. I would recommend N.Avasthi's practice book. For inorganic, learn ncert by heart and for organic, get a deeper insight in mechanisms.

For physics- You don't have much time on your hand so I would recommend H.C.Verma for problem solving. Solve each and every question. For some side topics you will have to refer ncert also like for some experimental parts.

For mathematics- This is the trickiest part. You'll  have to work the hardest in it. First, solve the complete K.C.Sinhs's book or R.D.Sharma's book. Then for higher level, I would suggest you to join the Distance Learning Program (DLP)  of any reputed coaching such a bansal or resonance. Solve their material from cover to cover.

The final step is your performance and calmness in examination hall. For that you can practice online mock tests again which are conducted by many reputed coaching.

one last thing I would say is not only IITs but NITs and IIITs are a very good option too. There are also many good private colleges available too. But if IIT is your dream, its worth taking a chance. Everything depends upon your consistency, regularity and will to do so. Even aday can take away your chance or give you a seat in IIT. It totally depens upon how you spend that day.