This is my claim , or the point I will prove in the following paragraph. All the sentences that follow this topic sentence must relate to it in some way. Like a thesis statement, a topic sentence makes a claim of some sort. As the thesis statement is the unifying force in the essay, so the topic sentence must be the unifying force in the paragraph. Further, as is the case with the thesis statement, when the topic sentence makes a claim, the paragraph which follows must expand, describe, or prove it in some way.
Topic sentences make a point and give reasons or examples to support it.
Finally, I wrap up the paragraph by stating exactly how topic sentences act rather like tiny thesis statements.