Hello Aspirant ,

I think you are talking about percentile because there is no percentage in JEE Mains. Since you got 70 percentile it is a very low score and at this score you won't be able to get NIT Tirichy anyway .

Even ST cateogry candidate require to have more than 99 percentile to get CSE in NIT Tirichy and atleast 93 percentile to get any branch like Chemical Engineering, and you are talking about reaching from 70 percentile to 99 percentile in just  two months preparation .

Let me tell you it is not impossible but only few candidates are able to do so . For achieving this you need to do a lot of hardwork and improvement .

You should stay away from all the distraction source and should study atleast 8 hrs a day apart from it you must find out your weak topics and try to improve them with also practicing questions of your strong topics simultaneously. You should join any online mock test so that you can give test and track your improvement , also practice privious year questions .

Apart from it just want to say even after doing hard labour if you can't get NIT Tirichy don't lose hope there are many other NITs which you can get by just scoring about 85 percentile as you belong to ST category. Also if you are a 12th student you can apply next year and improve your performance apart from it many other career options are also available , so be optimistic and prepare as hard as you can .

Hope this will help you.