Final selection and ranking in the Civil Services Examination is based on the 1750 marks of Mains written + 275 marks of Interview Test or Personality Test. However, there exists a significant variation in the marks of the candidates appearing for the Interview. Thus Interview Test makes significant difference in the selection of a candidate as well final ranking, thus allocation of service.
Interview Test is not simply test of knowledge, rather it is an assessment of overall personality. Thus preparation of interview is a continuing process, yet after the Main written exam there is sufficient time for its preparation. A good knowledge of fundamentals plus updates boosts up confidence and helps in answering interview questions precisely.
A candidate needs to pay attentions to multiple issues such as about the self, hobby/hobbies, home state, home district, service preferences, cadre preferences for IAS and IPS, earlier job(s)/posts (if any) if one worked, places where one spent significant part of life, occupation/profession of parents, or family business if any, subjects in earlier educational courses or optional subject in civil services preparation, etc.
Dressing descent and formal for the interview, greeting the panel chairperson and members, be honest if one does not know the answer rather than beating the bush, listen attentively, gracefully letting the members interrupt if they want to, neither speaking too much nor too little, being confident but not over-confident and too assertive even if one knows the issue very well, being polite and logical, not panicking if one does not know answer to any or some questions, giving straight and simple reply to a question, etc.
Why civil services as a career? If not civil services then what else? What are new non-conventional careers emerging now? Service preferences one has given and why? Cadre preferences for IAS and IPS one has given and why? What are opportunities and challenges in the Civil Services as a career? Is there any need for some major reforms in Civil Services? If yes, what? Is there any need for some major reforms in Cvil Services Examination? If yes, then what? How Civil Services can be made to contribute better for national building?
Apart from verbal communication, there is significant role of non-verbal communication in the conversation. So one needs to have a positive but descent body language which supports the communication and is courteous. One has to pay attention to facial expression, body movement, sitting posture, etc while the conversation takes place.