Hello Rahul,

75% is really not very bad score, you can get admission in many of the colleges with that score. If you are very sure about getting an IIT seat next year then you can absolutly consider that idea of taking a break for 1 year. If you are not sure and just wanna give it a shot then you better don't, because IIT coaching is not very cheap, so dont't waste your money on which you are very sure to just give a try. At the end it all depends on your intrest also, if you are very much intrested towards IIT then you can absolutly go for it or there are some collges which you should consider applying are,

1. SRM University, Chennai.

2. Hindustan University, Chennai.

3. Reva University, Banglore.

4. New horizon University, Banglore.

5. Geetams University, Vizag.

6. Panimalar College of Engineering, Chennai.

7. KL University, Andhra Pradesh.

Hope this Helps.

Good Luck! will be happy to help you with any other doubts.