Write down this paragraph, and take it to your supervisors and project coordinaters, making sure everyone is on the same page. Social security numbers will be used to uniquely identify each employee. For reporting purposes, an employee will designate his working hours under various categories. The categories to which an employee can assign his time is dependent upon which department the employee is in. Basically, look for nouns in your example paragraph, and these are often tables.
Adjectives are object columns.
Verbs are often relations. Preliminary table designs, data design outlines, technical specifications, and all other documents need to be grouped and filed for easy access. One of the main reasons to data model is to enhance your application's maintainability. Good documentation is important. Other important steps you can take to improve the maintainability of your program is to write self-documenting code.