• Donot take the interview casually.
• Never give an impression that you are not interested in a particular bank.
• Avoid hand and leg movements.
• Avoid long pauses while speaking
• Dont be numb during the interview. This shows the lack of interest in the conversation. So, do ask questions at times.
• Dont expose a lack of interest for a particular bank.

Assuming asking for IBPS clerk, You must be Graduate to apply for bank clerk  examand you can do your graduation in any of the course field as per your interest. For further information about you can go through with given below link.

IBPS Clerk

Assuming asking for IBPS clerk. You can apply online when its application form will announce. You should be graduate to apply for it. For further information about the eligibility you can go through with given below link.

IBPS Clerk

To become a bank clerk you need 12th pass with 60%  and if from reserved category then 55% in 12th.
You will have to check the advertisement dates for recruitment as it is available on various online and offline.

Maximum age limit is 28 years and minimum 18 years.
Initially the package will be less and it depends bank to bank but with years experience it shall increase.
Good Luck.

Ye, There is minimum age criteria for Clerk Exam candidates must be between 20 and 28 years. For further you can go through with given below link.

SBI Eligibility Criteria