What is a topic sentence and why should I use them?

A good structure is crucial for a good essay because it allows the reader to follow your line of argument and because it prevents any confusion. One of the key elements of a good paragraph, therefore, is a topic sentence. The topic sentence should stand at the beginning of every paragraph you write, be the first line - you can think of it as an overly detailed headline to the point you are going to make. This should allow the reader to focus not on WHAT you are proving but on HOW you will do it.