First thing to do before you decide to appear in any exams is to go through the syllabus thoroughly. Syllabus is the only document that tells you about the way to study that particular course. Syllabus clearly tells WHAT TO STUDY and WHAT NOT TO. An important thing to identify in any syllabus is its tone. Actually, syllabus tells you what are the expectations from you and reveals its scope at the same time. It also acquaints you with the logistics of the course itself. Once you are clear about the way to walk, you can, without any distractions, reach the destination. That's why syllabus is also called COURSE OF STUDY.
Please visit the official website of Public Service Commission and download the updated syllabus from there. Or you can also get the one for Section Officer from here as well. Click on the following links to download:
Under Integrated & Unified Examination System, the Examination Scheme overview is as follows:
1. Written Examination: First Phase and Second Phase
2. Final Examination: IT Skills Test, Group Test, and Interview
Paper I - Administrative Aptitude Test [Download PDF]
Second Phase
Paper II - Governance Systems [Download PDF]
Paper III - Contemporary Issues [Download PDF]
For Administration, Audit and Legislative Parliament Services only
Paper IV - Service Related [Download PDF]
For Foreign Service only
Extra Paper I - English Language [Download PDF]
Extra Paper II - Foreign Policy & International Relations [Download PDF]
Final Phase
IT Skills Test [Download PDF]
Group Test [Download PDF]
While going through syllabus, try to characterize the tone and figure out what actually are its expectations from you. Be sure that you won't start your study without being clear about the course contents. No matter how long it takes, please go through the syllabus and be clear about each and every topics it entails.
NOTE: Another important advice which you will hardly ever get from someone is to go through PSC Directives which inter alia provides handful of information about how the questions are formulated and answers are evaluated. Please go through this document which I have extracted from Public Service Commission Directives, 2067 which provides you an valuable insight prepare properly for the exams. I recommend you to read entire directives and regulations that are brought into effect by PSC.