A strong thesis statement avoids vague language and is specific and provocative.
It needs to hook the reader. Also, explain why the topic of your essay is important and why it should matter to the readers. The University of Maryland University College website says the conclusion should have a summary of the essay's major arguments and an explanation on how they are connected.
Now this opening sentence could in fact be your thesis statement. How hard is that? It needs to grab their attention right from the beginning.
Avoid the overused and unoriginal dictionary definition opening. You can elaborate on those main points and you can even refer to your thesis statement.
Follow the same format as the first body paragraph. It might be small by comparison but it still demands respect.
In other words start with a bang.