The personality is some thing that cannot be developed in few days. It is a continuous process since your childhood. But, you can modify it suitably to get good marks in the interview.
Some traits, which can be summarized below:
1. Suitability to a public career
2. Mental Caliber
3. Not only intellectual traits but also social traits
4. Interest in current affairs
5. Mental alertness
6. Critical powers of assimilation
7. Clear and logical exposition
8. Balance of judgment
9. Variety and depth of interest
10. Ability for social cohesion and leadership
11. Intellectual and moral integrity