You begin by searching for a position on USAjobs.gov and review the wording in the Job description which sounds like a good match. The best way to understand the requirements of the position is to compare your experience with what is stated under the job duties, qualifications and specialized experience. The resume will have to be created according to the words described in the job announcement. 

For example, selecting an Administrative Support Assistant will describe the duties as follows:

• Providing administrative/clerical support to a wide variety of complex, administrative and technical functions relating to the GEC Service Line.
• Responsible for the clinical and administrative functioning of the Service Line and maintains a clinical workload that includes the responsibility of providing supervision of physicians, nurse practitioners, nursing and clerical staff.
• Advises management and staff in the interpretation of application of administrative procedures.
• Responsible for the completion of the annual equipment inventory. Incumbent ensures that all equipment requests are adequate, appropriate, and required for program operation.
• Tracking furniture, ADP, equipment, and project needs for each fiscal year for the service line.
• Prepares paperwork, meets with managers, participates in meetings to prioritize needs with the service line, and may attend stations meetings on behalf of the GEC Service Line Manager.

The Qualifications will outline the Specialized Experience as follows:

Examples of specialized experience would typically include, but are not limited maintaining databases and utilizing various software programs; managing administrative activities; maintaining files of administration records, supplies, and equipment; managing computerized databases related to budget and financial information; analyze and measure the effectiveness, efficiency, and productivity of administrative programs; develops written and oral correspondence.