A thesis is the central idea of a piece of writing with the entire work developing and supporting the idea. Though sometimes unstated, a thesis should always govern a paper. It usually appears as a thesis statement somewhere in the paper, primarily in the opening paragraph.
What's the topic you want to write about?
What's your main opinion on this topic?
(Note: use the topic somewhere in this opinion statement and maybe the word "should")
What's the strongest argument supporting your opinion?
What's a second good argument that supports your opinion?
What's the main argument against your opinion?
What's a possible title for your Essay?