Eligibility totally depends upon your performance in interview. Be very bold, confident and good communication. Your eligibility test will depend upon post you are applying for but a common process they follow is reasoning test(be very attentive during test), maths(basic things), aptitude (keep a eagle eye on every word of the question). Your academics of 60% and above will help you as well. Google always looks for passion, innovation and dedication. Be passionate and show your ability from the first round itself and this will eventually get u a job in Google. It is quite tough to crack Google's second round where you need to go for a online test time will be very less and questions are little tough ones. If you cracked this round the last Hr round will be totally easy just be calm and show them your skills and positive attitude and job is all yours.