hi,

see to get admission in tier 1 btech college you must appear in entrance exam like jee main, mhtcet, wbjeeb, kcet, or any other state wise entrance test. however as per tamil nadu engineering admission, i.e tnea counselling admission in engineering colleges of tamil nadu is based on 12th score. students from tamil nadu as well as other state candidates satisfying the eligibility criteria may participate in the admission process. however there is numerous colleges of engineering course in india and the admission process differ college to college. also some of the private university has separate entrance test like amity university, lovely professional university. so you have to decide which course you want to pursue and from which state you want to study engineering course. also you must aware of the tuition fees for the particular colleges.

you may follow the below link to know about btech colleges and there admission process,

https://engineering.careers360.com/colleges/list-of-engineering-colleges-in-india

Hey Aspirant,

You have not clearly mentioned what location, course you want to take admission in so I could not go that much in detail. But, First of all, 78.7% in 12th is not bad. You can get admission in good colleges too. You just need to see and search as I also don't know what all entrance exams you have given or applied for. Keep yourself Updated with all the latest news.

Hope this helps,

All the best and thank you!