@Shazia
The other day I happned to have discussion with a person who qualified for DDO in 2003. He told me some tips regarding PCS interview
1. Dont mix this interview with CSS interview because in PCS members usually go out of the subjects. They mostly ask questions from your surroundings. If one belong to Sukkur they wil start questioning thigns related to sukkur.
2. Your obervation matters alot. They may ask you questions from the environment he or she belongs to..like..if one says he or she is interested in literature they will ask u literature.
3. Prepare introduction prior to interview..impressive introuction matters alot. This is the starting point and it this stage from where they set their scope of questions of interview. If one says in introduction that he or she likes sports then be ready for sports questions..
4. History and literature of Sindh must be studied because he or she has to serve in any part of sindh so he or she must know.
5. Last but not least, one should be rational and should set himself or herslef in discussion mode in interview.

I am also going to appear in interview on 17th June. So hopefully the above points would help me in interview. Miss Shazia, your interview is in july so i would be telling you my experience.