JEE Preparation

For Individual teachers:
Mathematics: Ashish Vishnoi (and Anurag Vishnoi) or Abhishek Gupta
Chemistry: Pankaj Sir and Nirmal Sir
Physics: definitely Vanish Srivastava. He is the best physics teacher in the whole Kakadeo. For Combined Coaching:
FITJEE
Vidyamandir Classes (though I don't really know how well is their Kanpur faculty because it is relatively new in Kanpur. Although Vidyamandir is a very reputed coaching in Delhi and has a very high selection rate and that too in good branches.

Please follow Arihant. This book is named as RD Sharma objective for IIT-JEE mathematics.

Grab this college. IET is one of the best college of Uttar Pardesh, and it is much better than some of the NITs and no doubt this college has a very good placement track and awesome study and entertainment environment.

If u want higher education prepare JEE, if u like normal education mean go with hsc.

You can try Akash, Janakpuri. Though they are an English-medium institute, if you raise your problem, they will teach you in normal day to day language.
Plus, they will help you improve your English as in engineering. Almost every lecture is taught in English only
or else you can join any local institute.
All the best.

Definitely, you should start preparing even if you get 100%
in the central board as the syllabus of 10th and JEE are different, moreover, JEE is harder when compared with 10th.

For that, you have to first go to your school from where you have cleared your class 12th, ask the procedure of the improvement, finish all the formalities and then get back to your JEE preparation.

I will prefer you not to opt for the Gaikwad Institutes for the preparation for JEE and CET, as their study material is not that much of worth that they charge for, there material is only for the CET and not for the JEE, so if you want to get quality education as well as the material of study I prefer you to go for the any other institute.

Then you should probably apply for counseling from General category if you are not able to correct at this point.

Since you are an aspirant of B.Tech in agriculture, you might not need coaching that much. Still, if you are planning to go to Kota then you might perform well and can also go for more good branches in many good colleges. But it's good that you have your goal clear. Work accordingly. Keep your spirit high.
All the best.