If you are "stuck" on an ancestor, pretend that you are creating a "resume" or "vita" for him (or her). Think about what skills he or she had, what his occupation was, what his educational level was, what you know about his work history, and what types of jobs he was probably qualified for.
For some of us, a great deal of this will consist of day labor or farm work. But think about what age the ancestor probably started working "at home" (if appropriate) and at what age he might have started working out side the home.
If nothing else, it might be an interesting thought exercise. For others, it might give you some actual research ideas.