I always tell my students to write their topic sentences based off the thesis of their paper. Every topic sentence should tie back to the thesis, even if it's just a referential point. Sometimes, students want to get the work done quickly, and for that to happen, the student needs to have an opinion. All of English rhetoric is based on opinions. Develop first an opinion on the topic of Facebook or social media. Then, create topic sentences that support that opinion.
For instance, say the student has developed this thesis for the paper: Facebook is an outmoded form of social media only used by old people.
If that is the case, then the student would need to develop three main arguments that support that thesis:
- Facebook tends to have an older demographic than newer social media technologies;
- Facebook does not allow as much video content as newer technologies, and it has become outmoded because younger audiences do not read as much or as well; and
- Facebook fails to keep up with the times by not attracting a younger audience.
These main three arguments could then be used to develop each paragraph. While this argument might be a little ridiculous, it should serve as a model to help people develop their ideas. Sometimes, people do well just starting to write paragraphs and then come up with the topic sentences later. Other people might do well with creating an outline and developing their topic sentences and arguments from there. Regardless, the best source for writing topic sentences is one's own opinions. Asking questions like, "What do I think about this?" or "Why is this important?" or "What data can support this opinion?" might also offer some useful starting positions for answering this question.