CBSE 10th

Yes you can get into IIM Ahmedabad if you score well between 95-99 percentile.
https://www.shiksha.com/mba/course/post-graduate-program-management-indian-institute-management-iim-a/1653

There are various fields in Diploma after completing 10th standard. IF you are looking in terms of scope then you can pursue mechanical engineering otherwise you may go for civil engineering.

Please check eligibility below.
Candidate must have completed graduation with at least 50% marks or equivalent CGPA (45% for SC/ST/PWD/DA) from a recognized University Final year student can also apply .Must have obtained valid percentile/score in CAT-2016/GMAT (at least 700) not before December 15, 2014(Overseas Indian candidates)
Note - It is mandatory for a final year student, who is provisionally admitted, to submit the mark sheet and degree certificate of the final year bachelors degree examination held on' or before June 30, 2017.

Yes chances are great with this score, you may also get good colleges like S.P Jain Mumbai. Check list of colleges under GMAT.
https://www.shiksha.com/mba/ranking/top-mba-colleges-india-accepting-gmat/2-2-0-0-310

After completing class 10th, you can choose either class 12th or can go for Diploma 3 year courses.

No, you have to clear your 12th standard first.

Hello Abhishek,
First, ask yourself what you want to be in life, your dreams.
You can opt for PCB if you want to become a doctor, dentist, physiotherapist, pharmacist, agriculture, veterinary doctor or scientist.
You can go for PCM in order to become an engineer, pharmacist, or scientist.
You can go for CEC, HEC or MEC for commerce or administrative jobs.
You can pursue law, hotel management or business management course after opting for any of the streams.

Hello Vikas,
Your question is not clear to us, kindly ask in simple way what you want to say.

Student should keep basics clear. Competitive exams tests students mainly on application part of the concepts. Clear and in-depth knowledge of basic concepts will help an individual to excel in competitive exams. Try to question ourselves over the concepts and formulas, figure out how any question can be solved in a simpler way. Approaching the same question with different ways will help you to strengthen the concept. Reference books helps in getting various types of problems, hence problems from reference books need to be solved regularly.